diff --git a/book/book.tex b/book/book.tex
index fe02ae4..1009a30 100644
--- a/book/book.tex
+++ b/book/book.tex
@@ -5621,7 +5621,7 @@ \section{{\tt break}}
 can check the condition anywhere in the loop (not just at the
 top) and you can express the stop condition affirmatively
 (``stop when this happens'') rather than negatively (``keep going
-until that happens'').
+until that doesn't happens'').
 
 
 \section{Square roots}