diff --git a/prologue/architecture.xml b/prologue/architecture.xml
index 75c29ce36..0a9c07599 100644
--- a/prologue/architecture.xml
+++ b/prologue/architecture.xml
@@ -17,7 +17,7 @@ is most compatible with both open source and proprietary software.</para>
 
 <para>On the other hand, the instructions in this book are known to work, with
 some modifications, with both Power PC and 64-bit AMD/Intel CPUs.  To build a
-system that utilizes these CPUs, the main prerequsite in addition to those on
+system that utilizes these CPUs, the main prerequisite in addition to those on
 the next few pages, is an existing system such as an earlier LFS system,
 Ubuntu, Red Hat/Fedora, SuSE, or other distribution that targets the system
 that you have.  Also note that a 32-bit system can be installed and used as a