diff --git a/book.tex b/book.tex
index 09cf14b..c7a4dfb 100644
--- a/book.tex
+++ b/book.tex
@@ -1193,7 +1193,7 @@ \subsection{Syntax}
   stdout > @
     sprintf
       "%b\n%b\n"
-      TREU
+      TRUE
       FALSE
 \end{ffcode}
 \textbf{Output}