diff --git a/en_US.ISO8859-1/books/porters-handbook/book.sgml b/en_US.ISO8859-1/books/porters-handbook/book.sgml
index 4e60e68dee..0e26ffed9e 100644
--- a/en_US.ISO8859-1/books/porters-handbook/book.sgml
+++ b/en_US.ISO8859-1/books/porters-handbook/book.sgml
@@ -8556,6 +8556,89 @@ CFLAGS+=        -DLUA_VERSION_STRING="${VER_STR}"
       <programlisting>USE_XFCE=        mcsmanager configenv</programlisting>
     </sect1>
 
+    <sect1 id="using-mozilla">
+      <title>Using Mozilla</title>
+
+	<table frame="none">
+	  <title>Variables for ports that use Mozilla</title>
+
+	  <tgroup cols="2">
+	    <tbody>
+
+	      <row>
+		<entry><makevar>USE_GECKO</makevar></entry>
+
+		<entry>Gecko backend the port can handle. Possible values:
+		  <literal>libxul</literal> (<filename>libxul.so</filename>),
+		  <literal>seamonkey</literal> (<filename>libgtkembedmoz.so</filename>,
+		  deprecated, shouldn't be used anymore).</entry>
+	      </row>
+	      <row>
+		<entry><makevar>USE_FIREFOX</makevar></entry>
+
+		<entry>The port requires Firefox as a runtime dependency.
+		  Possible values:
+		  <literal>yes</literal> (get default version),
+		  <literal>40</literal>, <literal>36</literal>,
+		  <literal>35</literal>.
+		  Default dependency is on version
+		  <literal>40</literal>.</entry>
+	      </row>
+	      <row>
+		<entry><makevar>USE_FIREFOX_BUILD</makevar></entry>
+
+		<entry>The port requires Firefox as a buildtime dependency.
+		  Possible values: see USE_FIREFOX.
+		  This automatically sets USE_FIREFOX and
+		  assigns the same value.</entry>
+	      </row>
+	      <row>
+		<entry><makevar>USE_SEAMONKEY</makevar></entry>
+
+		<entry>The port requires SeaMonkey as a runtime dependency.
+		  Possible values:
+		  <literal>yes</literal> (get default version),
+		  <literal>20</literal>, <literal>11</literal>
+		  (deprecated, shouldn't be used anymore).
+		  Default dependency is on version
+		  <literal>20</literal>.</entry>
+	      </row>
+	      <row>
+		<entry><makevar>USE_SEAMONKEY_BUILD</makevar></entry>
+
+		<entry>The port requires SeaMonkey as a buildtime dependency.
+		  Possible values: see USE_SEAMONKEY.
+		  This automatically sets USE_SEAMONKEY and
+		  assigns the same value.</entry>
+	      </row>
+	      <row>
+		<entry><makevar>USE_THUNDERBIRD</makevar></entry>
+
+		<entry>The port requires Thunderbird as a runtime dependency.
+		  Possible values:
+		  <literal>yes</literal> (get default version),
+		  <literal>31</literal>, <literal>30</literal>
+		  (deprecated, shouldn't be used anymore).
+		  Default dependency is on version
+		  <literal>31</literal>.</entry>
+	      </row>
+	      <row>
+		<entry><makevar>USE_THUNDERBIRD_BUILD</makevar></entry>
+
+		<entry>The port requires Thunderbird as a buildtime dependency.
+		  Possible values: see USE_THUNDERBIRD.
+		  This automatically sets USE_THUNDERBIRD
+		  and assigns the same value.</entry>
+	      </row>
+
+	    </tbody>
+	  </tgroup>
+	</table>
+      <para>A complete list of available variables can be found in
+	<filename>/usr/ports/Mk/bsd.gecko.mk</filename>.</para>
+    </sect1>
+
+
     <sect1 id="using-databases">
       <title>Using databases</title>