diff --git a/manual/preamble.tex b/manual/preamble.tex
index 56771382ad..af9fba904c 100644
--- a/manual/preamble.tex
+++ b/manual/preamble.tex
@@ -276,4 +276,8 @@
 \ifpdfoutput{}{\renewcommand{\Forward}[1]{$\triangleright${}#1}}
 
 \newcommand{\btnfnt}[1]{\textbf{#1}}
-%\hfuzz=2pt
\ No newline at end of file
+%\hfuzz=2pt
+
+% generate index
+\usepackage{makeidx}
+\makeindex