diff --git a/chapter04/creatingminlayout.xml b/chapter04/creatingminlayout.xml
index 6b339344b..cab023a49 100644
--- a/chapter04/creatingminlayout.xml
+++ b/chapter04/creatingminlayout.xml
@@ -39,4 +39,16 @@ esac</userinput></screen>
 
 <screen><userinput>mkdir -pv $LFS/tools</userinput></screen>
 
+  <note>
+    <para>
+      LFS editors have deliberately decided not to use a
+      <filename class="directory">/usr/lib64</filename> directory.  Several
+      steps are taken so that the toolchain does not use it. If for any
+      reason this directory appears (either because you made an error in
+      following the instructions, or because you install a binary package that
+      creates it after finishing LFS), it may break the instructions given in
+      the book. You should often ensure that this directory is non-existent.
+    </para>
+  </note>
+
 </sect1>
diff --git a/chapter07/creatingdirs.xml b/chapter07/creatingdirs.xml
index 35a0a9003..0bb75fd5d 100644
--- a/chapter07/creatingdirs.xml
+++ b/chapter07/creatingdirs.xml
@@ -68,6 +68,17 @@ install -dv -m 1777 /tmp /var/tmp</userinput></screen>
     directories that are really necessary. However, feel free to create more
     directories, if you wish.  </para>
 
+  <warning>
+    <para>
+      The FHS does not enforce the existence of the directory
+      <filename class="directory">/usr/lib64</filename>, and the LFS editors
+      have decided not to use it. For the instructions in LFS and BLFS to work,
+      it is imperative that this directory be non-existent. You should often
+      check that it does not exist, because it is easy to inadvertently
+      create it, which will likely break your system.
+    </para>
+  </warning>
+
   </sect2>
 
 </sect1>