--- a/CookBook/Tactical.thy	Thu Feb 26 12:16:24 2009 +0000
+++ b/CookBook/Tactical.thy	Thu Feb 26 13:46:05 2009 +0100
@@ -1323,7 +1323,7 @@
 text {*
 
   Conversions are a thin layer on top of Isabelle's inference kernel, and 
-  can be viewed be as a controllable, bare-bone version of Isabelle's simplifier.
+  can be viewed as a controllable, bare-bone version of Isabelle's simplifier.
   One difference between conversions and the simplifier is that the former
   act on @{ML_type cterm}s while the latter acts on @{ML_type thm}s. 
   However, we will also show in this section how conversions can be applied