diff --git a/src/assemblage.lua b/src/assemblage.lua
index 241525d..c2303f2 100644
--- a/src/assemblage.lua
+++ b/src/assemblage.lua
@@ -1,10 +1,15 @@
 --- Assemblage
+-- An Assemblage is a function that 'makes' an entity something.
+-- It does this by :give'ing or :ensure'ing Components, or by :assemble'ing the Entity.
 
 local Assemblage = {}
 Assemblage.__mt = {
    __index = Assemblage,
 }
 
+--- Creates a new Assemblage.
+-- @param assemble Function that assembles an Entity
+-- @return A new Assemblage
 function Assemblage.new(assemble)
    local assemblage = setmetatable({
       __assemble = assemble,
@@ -15,6 +20,11 @@ function Assemblage.new(assemble)
    return assemblage
 end
 
+--- Assembles an Entity.
+-- @see Entity:assemble
+-- @param e Entity to assemble
+-- @param ... Varargs to pass to the assemble function
+-- @ return self
 function Assemblage:assemble(e, ...)
    self.__assemble(e, ...)
 
diff --git a/src/assemblages.lua b/src/assemblages.lua
index f86f629..f34e3b9 100644
--- a/src/assemblages.lua
+++ b/src/assemblages.lua
@@ -1,4 +1,5 @@
--- Assemblages
+--- Assemblages
+-- Container for registered Assemblages
 
 local PATH = (...):gsub('%.[^%.]+$', '')
 
@@ -6,17 +7,20 @@ local Type = require(PATH..".type")
 
 local Assemblages = {}
 
+--- Registers an Assemblage.
+-- @param name Name to register under
+-- @param assemblage Assemblage to register
 function Assemblages.register(name, assemblage)
     if (type(name) ~= "string") then
         error("bad argument #1 to 'Assemblages.register' (string expected, got "..type(name)..")", 3)
     end
 
     if (not Type.isAssemblage(assemblage)) then
-        error("bad argument #2 to 'Assemblages.register' (assemblage expected, got "..type(world)..")", 3)
+        error("bad argument #2 to 'Assemblages.register' (assemblage expected, got "..type(assemblage)..")", 3)
     end
 
     if (rawget(Assemblages, name)) then
-        error("bad argument #2 to 'Assemblages.register' (Assemblage with name '"..name.."' is already registerd)", 3)
+        error("bad argument #2 to 'Assemblages.register' (Assemblage with name '"..name.."' was already registerd)", 3)
     end
 
     Assemblages[name] = assemblage
diff --git a/src/component.lua b/src/component.lua
index d288815..bf862a0 100644
--- a/src/component.lua
+++ b/src/component.lua
@@ -1,43 +1,46 @@
 --- Component
+-- A Component is a pure data container.
+-- A Component is contained by a single entity.
 
 local Component = {}
 Component.__mt = {
    __index = Component,
 }
 
---- Creates a new Component.
--- @param populate A function that populates the Bag with values
--- @return A Component object
+--- Creates a new ComponentClass.
+-- @param populate Function that populates a Component with values
+-- @return A new ComponentClass
 function Component.new(populate)
    if (type(populate) ~= "function" and type(populate) ~= "nil") then
       error("bad argument #1 to 'Component.new' (function/nil expected, got "..type(populate)..")", 2)
    end
 
-   local baseComponent = setmetatable({
+   local componentClass = setmetatable({
       __populate = populate,
 
-      __isBaseComponent = true,
+      __isComponentClass = true,
    }, Component.__mt)
 
-   baseComponent.__mt = {
-      __index = baseComponent
+   componentClass.__mt = {
+      __index = componentClass
    }
 
-   return baseComponent
+   return componentClass
 end
 
+--- Internal: Populates a Component with values
 function Component:__populate() -- luacheck: ignore
 end
 
---- Creates and initializes a new Component.
--- @param ... The values passed to the populate function
--- @return A new initialized Component
+--- Internal: Creates and populates a new Component.
+-- @param ... Varargs passed to the populate function
+-- @return A new populated Component
 function Component:__initialize(...)
    local component = setmetatable({
-      __baseComponent = self,
+      __componentClass = self,
 
       __isComponent     = true,
-      __isBaseComponent = false,
+      __isComponentClass = false,
    }, self)
 
    self.__populate(component, ...)
diff --git a/src/components.lua b/src/components.lua
index 2249774..76780de 100644
--- a/src/components.lua
+++ b/src/components.lua
@@ -1,4 +1,5 @@
 -- Components
+-- Container for registered ComponentClasss
 
 local PATH = (...):gsub('%.[^%.]+$', '')
 
@@ -6,24 +7,27 @@ local Type = require(PATH..".type")
 
 local Components = {}
 
-function Components.register(name, baseComponent)
+--- Registers a ComponentClass.
+-- @param name Name to register under
+-- @param componentClass ComponentClass to register
+function Components.register(name, componentClass)
     if (type(name) ~= "string") then
         error("bad argument #1 to 'Components.register' (string expected, got "..type(name)..")", 3)
     end
 
-    if (not Type.isBaseComponent(baseComponent)) then
-        error("bad argument #2 to 'Components.register' (BaseComponent expected, got "..type(baseComponent)..")", 3)
+    if (not Type.isComponentClass(componentClass)) then
+        error("bad argument #2 to 'Components.register' (ComponentClass expected, got "..type(componentClass)..")", 3)
     end
 
     if (rawget(Components, name)) then
-        error("bad argument #2 to 'Components.register' (BaseComponent with name '"..name.."' is already registerd)", 3)
+        error("bad argument #2 to 'Components.register' (ComponentClass with name '"..name.."' was already registerd)", 3)
     end
 
-    Components[name] = baseComponent
+    Components[name] = componentClass
 end
 
 return setmetatable(Components, {
     __index = function(_, name)
-        error("Attempt to index BaseComponent '"..tostring(name).."' that does not exist / was not registered", 2)
+        error("Attempt to index ComponentClass '"..tostring(name).."' that does not exist / was not registered", 2)
     end
 })
\ No newline at end of file
diff --git a/src/entity.lua b/src/entity.lua
index 38cc60d..c084039 100644
--- a/src/entity.lua
+++ b/src/entity.lua
@@ -1,4 +1,7 @@
 --- Entity
+-- Entities are the concrete objects that exist in your project.
+-- An Entity have Components and are processed by Systems.
+-- An Entity is contained by a maximum of 1 World.
 
 local PATH = (...):gsub('%.[^%.]+$', '')
 
@@ -9,7 +12,8 @@ Entity.__mt = {
    __index = Entity,
 }
 
---- Creates and initializes a new Entity.
+--- Creates a new Entity. Optionally adds it to a World.
+-- @param world Optional World to add the entity to
 -- @return A new Entity
 function Entity.new(world)
    if (world ~= nil and not Type.isWorld(world)) then
@@ -30,63 +34,73 @@ function Entity.new(world)
    return e
 end
 
-local function give(e, baseComponent, ...)
-   local component = baseComponent:__initialize(...)
+local function give(e, componentClass, ...)
+   local component = componentClass:__initialize(...)
 
-   e[baseComponent] = component
-   e.__components[baseComponent] = component
+   e[componentClass] = component
+   e.__components[componentClass] = component
 
    e:__dirty()
 end
 
-local function remove(e, baseComponent)
-   e[baseComponent] = nil
-   e.__components[baseComponent] = nil
+local function remove(e, componentClass)
+   e[componentClass] = nil
+   e.__components[componentClass] = nil
 
    e:__dirty()
 end
 
---- Gives an Entity a component with values.
--- @param component The Component to add
--- @param ... The values passed to the Component
+--- Gives an Entity a Component.
+-- If the Component already exists, it's overridden by this new Component
+-- @param componentClass ComponentClass to add an instance of
+-- @param ... varargs passed to the Component's populate function
 -- @return self
-function Entity:give(baseComponent, ...)
-   if not Type.isBaseComponent(baseComponent) then
-      error("bad argument #1 to 'Entity:give' (BaseComponent expected, got "..type(baseComponent)..")", 2)
+function Entity:give(componentClass, ...)
+   if not Type.isComponentClass(componentClass) then
+      error("bad argument #1 to 'Entity:give' (ComponentClass expected, got "..type(componentClass)..")", 2)
    end
 
-   give(self, baseComponent, ...)
+   give(self, componentClass, ...)
 
    return self
 end
 
-function Entity:ensure(baseComponent, ...)
-   if not Type.isBaseComponent(baseComponent) then
-      error("bad argument #1 to 'Entity:ensure' (BaseComponent expected, got "..type(baseComponent)..")", 2)
+--- Ensures an Entity to have a Component.
+-- If the Component already exists, no action is taken
+-- @param componentClass ComponentClass to add an instance of
+-- @param ... varargs passed to the Component's populate function
+-- @return self
+function Entity:ensure(componentClass, ...)
+   if not Type.isComponentClass(componentClass) then
+      error("bad argument #1 to 'Entity:ensure' (ComponentClass expected, got "..type(componentClass)..")", 2)
    end
 
-   if self[baseComponent] then
+   if self[componentClass] then
       return self
    end
 
-   give(self, baseComponent, ...)
+   give(self, componentClass, ...)
 
    return self
 end
 
---- Removes a component from an Entity.
--- @param component The Component to remove
+--- Removes a Component from an Entity.
+-- @param componentClass ComponentClass of the Component to remove
 -- @return self
-function Entity:remove(baseComponent)
-   if not Type.isBaseComponent(baseComponent) then
-      error("bad argument #1 to 'Entity:remove' (BaseComponent expected, got "..type(baseComponent)..")")
+function Entity:remove(componentClass)
+   if not Type.isComponentClass(componentClass) then
+      error("bad argument #1 to 'Entity:remove' (ComponentClass expected, got "..type(componentClass)..")")
    end
 
-   remove(self, baseComponent)
+   remove(self, componentClass)
 
    return self
 end
 
+--- Assembles an Entity.
+-- @see Assemblage:assemble
+-- @param assemblage Assemblage to assemble with
+-- @param ... Varargs to pass to the Assemblage's assemble function.
 function Entity:assemble(assemblage, ...)
    if not Type.isAssemblage(assemblage) then
       error("bad argument #1 to 'Entity:assemble' (Assemblage expected, got "..type(assemblage)..")")
@@ -98,6 +112,7 @@ function Entity:assemble(assemblage, ...)
 end
 
 --- Destroys the Entity.
+-- Removes the Entity from it's World if it's in one.
 -- @return self
 function Entity:destroy()
    if self.__world then
@@ -107,42 +122,54 @@ function Entity:destroy()
    return self
 end
 
+--- Internal: Tells the World it's in that this Entity is dirty.
+-- @return self
 function Entity:__dirty()
    if self.__world then
       self.__world:__dirtyEntity(self)
    end
+
+   return self
+end
+
+--- Returns true if the Entity has a Component.
+-- @param componentClass ComponentClass of the Component to check
+-- @return True if the Entity has the Component, false otherwise
+function Entity:has(componentClass)
+   if not Type.isComponentClass(componentClass) then
+      error("bad argument #1 to 'Entity:has' (ComponentClass expected, got "..type(componentClass)..")")
+   end
+
+   return self[componentClass] ~= nil
 end
 
 --- Gets a Component from the Entity.
--- @param component The Component to get
--- @return The Bag from the Component
-function Entity:get(baseComponent)
-   if not Type.isBaseComponent(baseComponent) then
-      error("bad argument #1 to 'Entity:get' (BaseComponent expected, got "..type(baseComponent)..")")
+-- @param componentClass ComponentClass of the Component to get
+-- @return The Component
+function Entity:get(componentClass)
+   if not Type.isComponentClass(componentClass) then
+      error("bad argument #1 to 'Entity:get' (ComponentClass expected, got "..type(componentClass)..")")
    end
 
-   return self[baseComponent]
-end
-
---- Returns true if the Entity has the Component.
--- @param component The Component to check against
--- @return True if the entity has the Bag. False otherwise
-function Entity:has(baseComponent)
-   if not Type.isBaseComponent(baseComponent) then
-      error("bad argument #1 to 'Entity:has' (BaseComponent expected, got "..type(baseComponent)..")")
-   end
-
-   return self[baseComponent] ~= nil
+   return self[componentClass]
 end
 
+--- Returns a table of all Components the Entity has.
+-- Warning: Do not modify this table.
+-- Use Entity:give/ensure/remove instead
+-- @return Table of all Components the Entity has
 function Entity:getComponents()
    return self.__components
 end
 
-function Entity:hasWorld()
+--- Returns true if the Entity is in a World.
+-- @return True if the Entity is in a World, false otherwise
+function Entity:inWorld()
    return self.__world and true or false
 end
 
+--- Returns the World the Entity is in.
+-- @return The World the Entity is in.
 function Entity:getWorld()
    return self.__world
 end
@@ -151,4 +178,4 @@ return setmetatable(Entity, {
    __call = function(_, ...)
       return Entity.new(...)
    end,
-})
+})
\ No newline at end of file
diff --git a/src/init.lua b/src/init.lua
index 66916db..b373989 100644
--- a/src/init.lua
+++ b/src/init.lua
@@ -47,13 +47,13 @@ Concord.assemblages = require(PATH..".assemblages")
 
 local function load(pathOrFiles, namespace)
    if (type(pathOrFiles) ~= "string" and type(pathOrFiles) ~= "table") then
-      error("bad argument #1 to 'load' (string/table of strings expected, got "..type(pathOrFiles)..")", 3) -- luacheck: ignore
+      error("bad argument #1 to 'load' (string/table of strings expected, got "..type(pathOrFiles)..")", 3)
    end
 
    if (type(pathOrFiles) == "string") then
       local info = love.filesystem.getInfo(pathOrFiles) -- luacheck: ignore
       if (info == nil or info.type ~= "directory") then
-         error("bad argument #1 to 'load' (path '"..pathOrFiles.."' not found)", 3) -- luacheck: ignore
+         error("bad argument #1 to 'load' (path '"..pathOrFiles.."' not found)", 3)
       end
 
       local files = love.filesystem.getDirectoryItems(pathOrFiles)
@@ -82,18 +82,34 @@ local function load(pathOrFiles, namespace)
    end
 end
 
+--- Loads ComponentClasses and puts them in the Components container.
+-- Accepts a table of paths to files: {"component_1", "component_2", "etc"}
+-- Accepts a path to a directory with ComponentClasses: "components"
+--@see Components
 function Concord.loadComponents(pathOrFiles)
    load(pathOrFiles, Concord.components)
 end
 
+--- Loads SystemClasses and puts them in the Systems container.
+-- Accepts a table of paths to files: {"system_1", "system_2", "etc"}
+-- Accepts a path to a directory with SystemClasses: "systems"
+--@see Systems
 function Concord.loadSystems(pathOrFiles)
    load(pathOrFiles, Concord.systems)
 end
 
+--- Loads Worlds and puts them in the Worlds container.
+-- Accepts a table of paths to files: {"world_1", "world_2", "etc"}
+-- Accepts a path to a directory with Worlds: "worlds"
+--@see Worlds
 function Concord.loadWorlds(pathOrFiles)
    load(pathOrFiles, Concord.worlds)
 end
 
+--- Loads Assemblages and puts them in the Assemblages container.
+-- Accepts a table of paths to files: {"assemblage_1", "assemblage_2", "etc"}
+-- Accepts a path to a directory with Assemblages: "assemblages"
+--@see Assemblages
 function Concord.loadAssemblages(pathOrFiles)
    load(pathOrFiles, Concord.assemblages)
 end
diff --git a/src/list.lua b/src/list.lua
index 94fee52..38ff949 100644
--- a/src/list.lua
+++ b/src/list.lua
@@ -1,4 +1,5 @@
 --- List
+-- Data structure that allows for fast removal at the cost of containing order.
 
 local List = {}
 List.__mt = {
@@ -6,7 +7,7 @@ List.__mt = {
 }
 
 --- Creates a new List.
--- @return A new list
+-- @return A new List
 function List.new()
    return setmetatable({
       size = 0,
@@ -14,9 +15,11 @@ function List.new()
 end
 
 --- Adds an object to the List.
--- @param obj The object to add
+-- Object must be of reference type
+-- Object may not be the string 'size'
+-- @param obj Object to add
 -- @return self
-function List:__add(obj) -- obj can not be a number and also not the string "size"
+function List:__add(obj)
    local size = self.size + 1
 
    self[size] = obj
@@ -27,7 +30,7 @@ function List:__add(obj) -- obj can not be a number and also not the string "siz
 end
 
 --- Removes an object from the List.
--- @param obj The object to remove
+-- @param obj Object to remove
 -- @return self
 function List:__remove(obj)
    local index = self[obj]
@@ -66,17 +69,23 @@ function List:__clear()
    return self
 end
 
---- Gets if the List has the object.
--- @param obj The object to search for
--- true if the list has the object, false otherwise
+--- Returns true if the List has the object.
+-- @param obj Object to check for
+-- @return True if the List has the object, false otherwise
 function List:has(obj)
    return self[obj] and true or false
 end
 
+--- Returns the object at an index.
+-- @param i Index to get from
+-- @return Object at the index
 function List:get(i)
    return self[i]
 end
 
+--- Returns the index of an object in the List.
+-- @param obj Object to get index of
+-- @return index of object in the List.
 function List:indexOf(obj)
    if (not self[obj]) then
       error("bad argument #1 to 'List:indexOf' (Object was not in List)", 2)
diff --git a/src/pool.lua b/src/pool.lua
index 1b7be39..4cde567 100644
--- a/src/pool.lua
+++ b/src/pool.lua
@@ -1,4 +1,6 @@
 --- Pool
+-- A Pool is used to iterate over Entities with a specific Components
+-- A Pool contain a any amount of Entities.
 
 local PATH = (...):gsub('%.[^%.]+$', '')
 
@@ -10,8 +12,8 @@ Pool.__mt = {
 }
 
 --- Creates a new Pool
--- @param name Identifier for the Pool.
--- @param filter Table containing the required Components
+-- @param name Name for the Pool.
+-- @param filter Table containing the required BaseComponents
 -- @return The new Pool
 function Pool.new(name, filter)
    local pool = setmetatable(List(), Pool.__mt)
@@ -25,7 +27,7 @@ function Pool.new(name, filter)
 end
 
 --- Checks if an Entity is eligible for the Pool.
--- @param e The Entity to check
+-- @param e Entity to check
 -- @return True if the entity is eligible, false otherwise
 function Pool:__eligible(e)
    for _, component in ipairs(self.__filter) do
@@ -37,27 +39,46 @@ function Pool:__eligible(e)
    return true
 end
 
+--- Internal: Adds an Entity to the Pool.
+-- @param e Entity to add
+-- @return self
 function Pool:__add(e)
    List.__add(self, e)
    self:onEntityAdded(e)
+
+   return self
 end
 
+--- Internal: Removed an Entity from the Pool.
+-- @param e Entity to remove
+-- @return self
 function Pool:__remove(e)
    List.__remove(self, e)
    self:onEntityRemoved(e)
+
+   return self
 end
 
+--- Gets the name of the Pool
+-- @return Name of the Pool.
 function Pool:getName()
    return self.__name
 end
 
+--- Gets the filter of the Pool.
+-- Warning: Do not modify this filter.
+-- @return Filter of the Pool.
 function Pool:getFilter()
    return self.__filter
 end
 
+--- Callback for when an Entity is added to the Pool.
+-- @param e Entity that was added.
 function Pool:onEntityAdded(e) -- luacheck: ignore
 end
 
+-- Callback for when an Entity is removed from the Pool.
+-- @param e Entity that was removed.
 function Pool:onEntityRemoved(e)  -- luacheck: ignore
 end
 
diff --git a/src/system.lua b/src/system.lua
index 4e0b778..5c12d39 100644
--- a/src/system.lua
+++ b/src/system.lua
@@ -1,4 +1,7 @@
 --- System
+-- A System iterates over Entities. From these Entities its get Components and modify them.
+-- A System contains 1 or more Pools.
+-- A System is contained by 1 World.
 
 local PATH = (...):gsub('%.[^%.]+$', '')
 
@@ -11,7 +14,7 @@ local System = {
 
 System.mt = {
    __index = System,
-   __call  = function(baseSystem, world)
+   __call  = function(systemClass, world)
       local system = setmetatable({
          __enabled = true,
 
@@ -19,8 +22,8 @@ System.mt = {
          __world = world,
 
          __isSystem = true,
-         __isBaseSystem = false, -- Overwrite value from baseSystem
-      }, baseSystem)
+         __isSystemClass = false, -- Overwrite value from systemClass
+      }, systemClass)
 
       -- Optimization: We deep copy the World class into our instance of a world.
       -- This grants slightly faster access times at the cost of memory.
@@ -29,8 +32,8 @@ System.mt = {
          Utils.shallowCopy(System, system)
       end
 
-      for _, filter in pairs(baseSystem.__filter) do
-         local pool = system:__buildPool(filter)
+      for _, filter in pairs(systemClass.__filter) do
+         local pool = system.__buildPool(filter)
          if not system[pool.__name] then
             system[pool.__name]                 = pool
             system.__pools[#system.__pools + 1] = pool
@@ -45,39 +48,40 @@ System.mt = {
    end,
 }
 
---- Creates a new System prototype.
+--- Creates a new SystemClass.
 -- @param ... Variable amounts of filters
--- @return A new System prototype
+-- @return A new SystemClass
 function System.new(...)
-   local baseSystem = setmetatable({
-      __isBaseSystem = true,
+   local systemClass = setmetatable({
+      __isSystemClass = true,
       __filter = {...},
    }, System.mt)
-   baseSystem.__index = baseSystem
+   systemClass.__index = systemClass
 
-   return baseSystem
+   return systemClass
 end
 
---- Builds a Pool for the System.
+--- Internal: Builds a Pool for the System.
 -- @param baseFilter The 'raw' Filter
 -- @return A new Pool
-function System:__buildPool(baseFilter) -- luacheck: ignore
+function System.__buildPool(baseFilter)
    local name   = "pool"
    local filter = {}
 
-   for _, v in ipairs(baseFilter) do
-      if type(v) == "table" then
-         filter[#filter + 1] = v
-      elseif type(v) == "string" then
-         name = v
+   for _, value in ipairs(baseFilter) do
+      if type(value) == "table" then
+         filter[#filter + 1] = value
+      elseif type(value) == "string" then
+         name = value
       end
    end
 
    return Pool(name, filter)
 end
 
---- Checks and applies an Entity to the System's pools.
+--- Internal: Evaluates an Entity for all the System's Pools.
 -- @param e The Entity to check
+-- @return self
 function System:__evaluate(e)
    for _, pool in ipairs(self.__pools) do
       local has  = pool:has(e)
@@ -93,8 +97,9 @@ function System:__evaluate(e)
    return self
 end
 
---- Remove an Entity from the System.
+--- Internal: Removes an Entity from the System.
 -- @param e The Entity to remove
+-- @return self
 function System:__remove(e)
    for _, pool in ipairs(self.__pools) do
       if pool:has(e) then
@@ -105,6 +110,8 @@ function System:__remove(e)
    return self
 end
 
+--- Internal: Clears all Entities from the System.
+-- @return self
 function System:clear()
    for i = 1, #self.__pools do
       self.__pools[i]:__clear()
@@ -113,59 +120,68 @@ function System:clear()
    return self
 end
 
+--- Enables the System.
+-- @return self
 function System:enable()
    self:setEnabled(true)
 
    return self
 end
 
+--- Disables the System.
+-- @return self
 function System:disable()
    self:setEnabled(false)
 
    return self
 end
 
+--- Toggles if the System is enabled.
+-- @return self
 function System:toggleEnable()
    self:setEnabled(not self.__enabled)
 
    return self
 end
 
+--- Sets if the System is enabled
+-- @param enable Enable
+-- @return self
 function System:setEnabled(enable)
    if (not self.__enabled and enable) then
       self.__enabled = true
-      self:onEnabledCallback()
+      self:onEnabled()
    elseif (self.__enabled and not enable) then
       self.__enabled = false
-      self:onDisabledCallback()
+      self:onDisabled()
    end
 
    return self
 end
 
+--- Returns is the System is enabled
+-- @return True if the System is enabled, false otherwise
 function System:isEnabled()
    return self.__enabled
 end
 
 --- Returns the World the System is in.
--- @return The world the system is in
+-- @return The World the System is in
 function System:getWorld()
    return self.__world
 end
 
---- Default callback for system initialization.
+--- Callback for system initialization.
 -- @param world The World the System was added to
 function System:init(world) -- luacheck: ignore
 end
 
--- Default callback for when a System's callback is enabled.
--- @param callbackName The name of the callback that was enabled
-function System:onEnabledCallback(callbackName) -- luacheck: ignore
+-- Callback for when a System is enabled.
+function System:onEnabled() -- luacheck: ignore
 end
 
--- Default callback for when a System's callback is disabled.
--- @param callbackName The name of the callback that was disabled
-function System:onDisabledCallback(callbackName) -- luacheck: ignore
+-- Callback for when a System is disabled.
+function System:onDisabled() -- luacheck: ignore
 end
 
 return setmetatable(System, {
diff --git a/src/systems.lua b/src/systems.lua
index 4f84472..81e6b2e 100644
--- a/src/systems.lua
+++ b/src/systems.lua
@@ -1,4 +1,5 @@
--- Systems
+--- Systems
+-- Container for registered SystemClasses
 
 local PATH = (...):gsub('%.[^%.]+$', '')
 
@@ -6,20 +7,23 @@ local Type = require(PATH..".type")
 
 local Systems = {}
 
-function Systems.register(name, system)
+--- Registers a SystemClass.
+-- @param name Name to register under
+-- @param systemClass SystemClass to register
+function Systems.register(name, systemClass)
     if (type(name) ~= "string") then
         error("bad argument #1 to 'Systems.register' (string expected, got "..type(name)..")", 3)
     end
 
-    if (not Type.isBaseSystem(system)) then
-        error("bad argument #2 to 'Systems.register' (baseSystem expected, got "..type(system)..")", 3)
+    if (not Type.isSystemClass(systemClass)) then
+        error("bad argument #2 to 'Systems.register' (systemClass expected, got "..type(systemClass)..")", 3)
     end
 
     if (rawget(Systems, name)) then
         error("bad argument #2 to 'Systems.register' (System with name '"..name.."' is already registerd)", 3)
     end
 
-    Systems[name] = system
+    Systems[name] = systemClass
 end
 
 return setmetatable(Systems, {
diff --git a/src/type.lua b/src/type.lua
index a7ba264..9a882a8 100644
--- a/src/type.lua
+++ b/src/type.lua
@@ -1,31 +1,53 @@
--- Type
+--- Type
+-- Helper module to do easy type checking for Concord types
 
 local Type = {}
 
+--- Returns if object is an Entity.
+-- @param t Object to check
+-- @return True if object is an Entity, false otherwise
 function Type.isEntity(t)
    return type(t) == "table" and t.__isEntity or false
 end
 
-function Type.isBaseComponent(t)
-   return type(t) == "table" and t.__isBaseComponent or false
+--- Returns if object is a ComponentClass.
+-- @param t Object to check
+-- @return True if object is an ComponentClass, false otherwise
+function Type.isComponentClass(t)
+   return type(t) == "table" and t.__isComponentClass or false
 end
 
+--- Returns if object is a Component.
+-- @param t Object to check
+-- @return True if object is an Component, false otherwise
 function Type.isComponent(t)
    return type(t) == "table" and t.__isComponent or false
 end
 
-function Type.isBaseSystem(t)
-   return type(t) == "table" and t.__isBaseSystem or false
+--- Returns if object is a SystemClass.
+-- @param t Object to check
+-- @return True if object is an SystemClass, false otherwise
+function Type.isSystemClass(t)
+   return type(t) == "table" and t.__isSystemClass or false
 end
 
+--- Returns if object is a System.
+-- @param t Object to check
+-- @return True if object is an System, false otherwise
 function Type.isSystem(t)
    return type(t) == "table" and t.__isSystem or false
 end
 
+--- Returns if object is a World.
+-- @param t Object to check
+-- @return True if object is an World, false otherwise
 function Type.isWorld(t)
    return type(t) == "table" and t.__isWorld or false
 end
 
+--- Returns if object is an Assemblage.
+-- @param t Object to check
+-- @return True if object is an Assemblage, false otherwise
 function Type.isAssemblage(t)
    return type(t) == "table" and t.__isAssemblage or false
 end
diff --git a/src/utils.lua b/src/utils.lua
index 43adf6c..6372b5b 100644
--- a/src/utils.lua
+++ b/src/utils.lua
@@ -1,5 +1,11 @@
+--- Utils
+-- Helper module for misc operations
+
 local Utils = {}
 
+--- Does a shallow copy of a table and appends it to a target table.
+-- @param orig Table to copy
+-- @param target Table to append to
 function Utils.shallowCopy(orig, target)
 	for key, value in pairs(orig) do
 		target[key] = value
diff --git a/src/world.lua b/src/world.lua
index f15a14d..a8c7953 100644
--- a/src/world.lua
+++ b/src/world.lua
@@ -1,4 +1,8 @@
 --- World
+-- A World is a collection of Systems and Entities
+-- A world emits to let Systems iterate
+-- A World contains any amount of Systems
+-- A World contains any amount of Entities
 
 local PATH = (...):gsub('%.[^%.]+$', '')
 
@@ -42,7 +46,7 @@ function World.new()
 end
 
 --- Adds an Entity to the World.
--- @param e The Entity to add
+-- @param e Entity to add
 -- @return self
 function World:addEntity(e)
    if not Type.isEntity(e) then
@@ -59,8 +63,8 @@ function World:addEntity(e)
    return self
 end
 
---- Removes an entity from the World.
--- @param e The Entity to mark
+--- Removes an Entity from the World.
+-- @param e Entity to remove
 -- @return self
 function World:removeEntity(e)
    if not Type.isEntity(e) then
@@ -72,13 +76,18 @@ function World:removeEntity(e)
    return self
 end
 
+--- Internal: Marks an Entity as dirty.
+-- @see Entity:__dirty
+-- @param e Entity to mark as dirty
 function World:__dirtyEntity(e)
    if not self.__dirty:has(e) then
       self.__dirty:__add(e)
    end
 end
 
-
+--- Internal: Flushes all changes to Entities.
+-- This processes all entities. Adding and removing entities, as well as reevaluating dirty entities.
+-- @see System:__evaluate
 -- @return self
 function World:__flush()
    -- Early out
@@ -135,26 +144,37 @@ function World:__flush()
    return self
 end
 
-local blacklistedSystemMethods = {
+-- These functions won't be seen as callbacks that will be emitted to.
+local blacklistedSystemFunctions = {
    "init",
+   "onEnabled",
+   "onDisabled",
 }
 
-function World:addSystem(baseSystem)
-   if (not Type.isBaseSystem(baseSystem)) then
-      error("bad argument #1 to 'World:addSystems' (baseSystem expected, got "..type(baseSystem)..")", 2)
+--- Adds a System to the World.
+-- Callbacks are registered automatically
+-- Entities added before are added to the System retroactively
+-- @see World:emit
+-- @param systemClass SystemClass of System to add
+-- @return self
+function World:addSystem(systemClass)
+   if (not Type.isSystemClass(systemClass)) then
+      error("bad argument #1 to 'World:addSystems' (SystemClass expected, got "..type(systemClass)..")", 2)
    end
 
-   -- TODO: Check if baseSystem was already added
+   if (self.__systemLookup[systemClass]) then
+      error("bad argument #1 to 'World:addSystems' (SystemClass was already added to World)", 2)
+   end
 
    -- Create instance of system
-   local system = baseSystem(self)
+   local system = systemClass(self)
 
-   self.__systemLookup[baseSystem] = system
+   self.__systemLookup[systemClass] = system
    self.systems:__add(system)
 
-   for callbackName, callback in pairs(baseSystem) do
+   for callbackName, callback in pairs(systemClass) do
       -- Skip callback if its blacklisted
-      if (not blacklistedSystemMethods[callbackName]) then
+      if (not blacklistedSystemFunctions[callbackName]) then
          -- Make container for all listeners of the callback if it does not exist yet
          if (not self.events[callbackName]) then
             self.events[callbackName] = {}
@@ -173,43 +193,59 @@ function World:addSystem(baseSystem)
    for j = 1, self.entities.size do
       system:__evaluate(self.entities[j])
    end
+
+   return self
 end
 
+--- Adds multiple Systems to the World.
+-- Callbacks are registered automatically
+-- @see World:addSystem
+-- @see World:emit
+-- @param ... SystemClasses of Systems to add
+-- @return self
 function World:addSystems(...)
    for i = 1, select("#", ...) do
-      local baseSystem = select(i, ...)
+      local systemClass = select(i, ...)
 
-      self:addSystem(baseSystem)
-   end
-end
-
-
-function World:hasSystem(baseSystem)
-   if not Type.isBaseSystem(baseSystem) then
-      error("bad argument #1 to 'World:getSystem' (baseSystem expected, got "..type(baseSystem)..")", 2)
+      self:addSystem(systemClass)
    end
 
-   return self.__systemLookup[baseSystem] and true or false
+   return self
 end
 
-function World:getSystem(baseSystem)
-   if not Type.isBaseSystem(baseSystem) then
-      error("bad argument #1 to 'World:getSystem' (baseSystem expected, got "..type(baseSystem)..")", 2)
+--- Returns if the World has a System.
+-- @param systemClass SystemClass of System to check for
+-- @return True if World has System, false otherwise
+function World:hasSystem(systemClass)
+   if not Type.isSystemClass(systemClass) then
+      error("bad argument #1 to 'World:getSystem' (systemClass expected, got "..type(systemClass)..")", 2)
    end
 
-   return self.__systemLookup[baseSystem]
+   return self.__systemLookup[systemClass] and true or false
 end
 
---- Emits an Event in the World.
--- @param eventName The Event that should be emitted
--- @param ... Parameters passed to listeners
+--- Gets a System from the World.
+-- @param systemClass SystemClass of System to get
+-- @return System to get
+function World:getSystem(systemClass)
+   if not Type.isSystemClass(systemClass) then
+      error("bad argument #1 to 'World:getSystem' (systemClass expected, got "..type(systemClass)..")", 2)
+   end
+
+   return self.__systemLookup[systemClass]
+end
+
+--- Emits a callback in the World.
+-- Calls all functions with the functionName of added Systems
+-- @param functionName Name of functions to call.
+-- @param ... Parameters passed to System's functions
 -- @return self
-function World:emit(callbackName, ...)
-   if not callbackName or type(callbackName) ~= "string" then
-      error("bad argument #1 to 'World:emit' (String expected, got "..type(callbackName)..")")
+function World:emit(functionName, ...)
+   if not functionName or type(functionName) ~= "string" then
+      error("bad argument #1 to 'World:emit' (String expected, got "..type(functionName)..")")
    end
 
-   local listeners = self.events[callbackName]
+   local listeners = self.events[functionName]
 
    if listeners then
       for i = 1, #listeners do
@@ -233,15 +269,19 @@ function World:clear()
       self:removeEntity(self.entities[i])
    end
 
+   for i = 1, self.systems.size do
+      self.systems[i]:clear()
+   end
+
    return self
 end
 
---- Default callback for adding an Entity.
+--- Callback for when an Entity is added to the World.
 -- @param e The Entity that was added
 function World:onEntityAdded(e) -- luacheck: ignore
 end
 
---- Default callback for removing an Entity.
+--- Callback for when an Entity is removed from the World.
 -- @param e The Entity that was removed
 function World:onEntityRemoved(e) -- luacheck: ignore
 end
diff --git a/src/worlds.lua b/src/worlds.lua
index 2f8f5a8..0ec2574 100644
--- a/src/worlds.lua
+++ b/src/worlds.lua
@@ -1,4 +1,5 @@
--- Worlds
+--- Worlds
+-- Container for registered Worlds
 
 local PATH = (...):gsub('%.[^%.]+$', '')
 
@@ -6,6 +7,9 @@ local Type = require(PATH..".type")
 
 local Worlds = {}
 
+--- Registers a World.
+-- @param name Name to register under
+-- @param world World to register
 function Worlds.register(name, world)
     if (type(name) ~= "string") then
         error("bad argument #1 to 'Worlds.register' (string expected, got "..type(name)..")", 3)