diff --git a/book/book.tex b/book/book.tex
index 81cdcea3..bc62735f 100644
--- a/book/book.tex
+++ b/book/book.tex
@@ -633,7 +633,7 @@ \chapter{Complexity Science}
 
 \section{The changing criteria of science}
 
-Complexity science is not just a different set of mdoels; it is also a
+Complexity science is not just a different set of models; it is also a
 gradual shift in the criteria models are judged by, and in the kinds
 of models that are considered acceptable.