diff --git a/doc/keywords.txt b/doc/keywords.txt
index 8e5825d..211cd4b 100644
--- a/doc/keywords.txt
+++ b/doc/keywords.txt
@@ -19,6 +19,7 @@ BOOST_PP_ENUM_SHIFTED_PARAMS
 BOOST_PP_EQUAL
 BOOST_PP_EQUAL_D
 BOOST_PP_EXPAND
+BOOST_PP_EXPR_IF
 BOOST_PP_FOR
 BOOST_PP_GREATER
 BOOST_PP_GREATER_D
@@ -26,7 +27,6 @@ BOOST_PP_GREATER_EQUAL
 BOOST_PP_GREATER_EQUAL_D
 BOOST_PP_IDENTITY
 BOOST_PP_IF
-BOOST_PP_IF_THEN
 BOOST_PP_INC
 BOOST_PP_LESS
 BOOST_PP_LESS_D
diff --git a/doc/reference/expand.htm b/doc/reference/expand.htm
index ce7fd8f..3be5eaf 100644
--- a/doc/reference/expand.htm
+++ b/doc/reference/expand.htm
@@ -19,7 +19,7 @@
 
 <hr>
 
-<a href="enum_shifted_params.htm">Prev</a> <a href="for.htm">Next</a> <a href="index.htm#Macros">Macros</a> <a href="index.htm#Headers">Headers</a>
+<a href="enum_shifted_params.htm">Prev</a> <a href="expr_if.htm">Next</a> <a href="index.htm#Macros">Macros</a> <a href="index.htm#Headers">Headers</a>
 <hr>
 
 <h1>#include &lt;<a href="../../../../boost/preprocessor/expand.hpp">boost/preprocessor/expand.hpp</a>&gt;</h1>
@@ -30,7 +30,7 @@
  <p>Essentially macro expands the parameter <code>X</code> twice.</p> 
 <hr>
 
-<a href="enum_shifted_params.htm">Prev</a> <a href="for.htm">Next</a> <a href="index.htm#Macros">Macros</a> <a href="index.htm#Headers">Headers</a>
+<a href="enum_shifted_params.htm">Prev</a> <a href="expr_if.htm">Next</a> <a href="index.htm#Macros">Macros</a> <a href="index.htm#Headers">Headers</a>
 <hr>
 
 <p>Revised <!--webbot bot="Timestamp" s-type="EDITED" s-format="%d %b %Y" startspan --><!--webbot bot="Timestamp" endspan i-checksum="15246" --></p>
diff --git a/doc/reference/if_then.htm b/doc/reference/expr_if.htm
similarity index 62%
rename from doc/reference/if_then.htm
rename to doc/reference/expr_if.htm
index 7b1d6f7..b87c9b4 100644
--- a/doc/reference/if_then.htm
+++ b/doc/reference/expr_if.htm
@@ -19,21 +19,26 @@
 
 <hr>
 
-<a href="if.htm">Prev</a> <a href="inc.htm">Next</a> <a href="index.htm#Macros">Macros</a> <a href="index.htm#Headers">Headers</a>
+<a href="expand.htm">Prev</a> <a href="for.htm">Next</a> <a href="index.htm#Macros">Macros</a> <a href="index.htm#Headers">Headers</a>
 <hr>
 
-<h1>#include &lt;<a href="../../../../boost/preprocessor/if_then.hpp">boost/preprocessor/if_then.hpp</a>&gt;</h1>
+<h1>#include &lt;<a href="../../../../boost/preprocessor/expr_if.hpp">boost/preprocessor/expr_if.hpp</a>&gt;</h1>
 
 <hr>
 
-<h2><a name="BOOST_PP_IF_THEN">#define BOOST_PP_IF_THEN</a>(C,T)</h2>
- <p>Expands to <code>T</code> if <code>C != 0</code> and to nothing if <code>C == 0</code>.</p>
+<h2><a name="BOOST_PP_EXPR_IF">#define BOOST_PP_EXPR_IF</a>(C,E)</h2>
+ <p>Expands to <code>E</code> if <code>C != 0</code> and to nothing if <code>C == 0</code>.</p>
 
-<p>For example, <code><a href="if_then.htm#BOOST_PP_IF_THEN">BOOST_PP_IF_THEN</a>(1,^)</code> expands to <code>^</code>.</p>
+<p>For example, <code><a href="expr_if.htm#BOOST_PP_EXPR_IF">BOOST_PP_EXPR_IF</a>(1,^)</code> expands to <code>^</code>.</p>
+
+<h3>See</h3>
+<ul>
+  <li><a href="if.htm#BOOST_PP_IF">BOOST_PP_IF</a>()</li>
+</ul>
 
 <hr>
 
-<a href="if.htm">Prev</a> <a href="inc.htm">Next</a> <a href="index.htm#Macros">Macros</a> <a href="index.htm#Headers">Headers</a>
+<a href="expand.htm">Prev</a> <a href="for.htm">Next</a> <a href="index.htm#Macros">Macros</a> <a href="index.htm#Headers">Headers</a>
 <hr>
 
 <p>Revised <!--webbot bot="Timestamp" s-type="EDITED" s-format="%d %b %Y" startspan --><!--webbot bot="Timestamp" endspan i-checksum="15246" --></p>
diff --git a/doc/reference/for.htm b/doc/reference/for.htm
index c585080..cc5da2a 100644
--- a/doc/reference/for.htm
+++ b/doc/reference/for.htm
@@ -19,7 +19,7 @@
 
 <hr>
 
-<a href="expand.htm">Prev</a> <a href="identity.htm">Next</a> <a href="index.htm#Macros">Macros</a> <a href="index.htm#Headers">Headers</a>
+<a href="expr_if.htm">Prev</a> <a href="identity.htm">Next</a> <a href="index.htm#Macros">Macros</a> <a href="index.htm#Headers">Headers</a>
 <hr>
 
 <h1>#include &lt;<a href="../../../../boost/preprocessor/for.hpp">boost/preprocessor/for.hpp</a>&gt;</h1>
@@ -89,7 +89,7 @@ invoking <a href="for.htm#BOOST_PP_FOR">BOOST_PP_FOR</a>##R() directly.</p>
 
 <hr>
 
-<a href="expand.htm">Prev</a> <a href="identity.htm">Next</a> <a href="index.htm#Macros">Macros</a> <a href="index.htm#Headers">Headers</a>
+<a href="expr_if.htm">Prev</a> <a href="identity.htm">Next</a> <a href="index.htm#Macros">Macros</a> <a href="index.htm#Headers">Headers</a>
 <hr>
 
 <p>Revised <!--webbot bot="Timestamp" s-type="EDITED" s-format="%d %b %Y" startspan --><!--webbot bot="Timestamp" endspan i-checksum="15246" --></p>
diff --git a/doc/reference/if.htm b/doc/reference/if.htm
index dd0e053..51fda0d 100644
--- a/doc/reference/if.htm
+++ b/doc/reference/if.htm
@@ -19,7 +19,7 @@
 
 <hr>
 
-<a href="identity.htm">Prev</a> <a href="if_then.htm">Next</a> <a href="index.htm#Macros">Macros</a> <a href="index.htm#Headers">Headers</a>
+<a href="identity.htm">Prev</a> <a href="inc.htm">Next</a> <a href="index.htm#Macros">Macros</a> <a href="index.htm#Headers">Headers</a>
 <hr>
 
 <h1>#include &lt;<a href="../../../../boost/preprocessor/if.hpp">boost/preprocessor/if.hpp</a>&gt;</h1>
@@ -32,6 +32,11 @@
 
 <p>For example, <code><a href="if.htm#BOOST_PP_IF">BOOST_PP_IF</a>(0,1,2)</code> expands to <code>2</code>.</p>
 
+<h3>See</h3>
+<ul>
+  <li><a href="expr_if.htm#BOOST_PP_EXPR_IF">BOOST_PP_EXPR_IF</a>()</li>
+</ul>
+
 <h3>Test</h3>
 <ul>
   <li><a href="../../test/preprocessor_test.cpp">preprocessor_test.cpp</a></li>
@@ -43,7 +48,7 @@
  <p>Obsolete. Use <a href="if.htm#BOOST_PP_IF">BOOST_PP_IF</a>().</p> 
 <hr>
 
-<a href="identity.htm">Prev</a> <a href="if_then.htm">Next</a> <a href="index.htm#Macros">Macros</a> <a href="index.htm#Headers">Headers</a>
+<a href="identity.htm">Prev</a> <a href="inc.htm">Next</a> <a href="index.htm#Macros">Macros</a> <a href="index.htm#Headers">Headers</a>
 <hr>
 
 <p>Revised <!--webbot bot="Timestamp" s-type="EDITED" s-format="%d %b %Y" startspan --><!--webbot bot="Timestamp" endspan i-checksum="15246" --></p>
diff --git a/doc/reference/inc.htm b/doc/reference/inc.htm
index 265795c..fd764e3 100644
--- a/doc/reference/inc.htm
+++ b/doc/reference/inc.htm
@@ -19,7 +19,7 @@
 
 <hr>
 
-<a href="if_then.htm">Prev</a> <a href="limits.htm">Next</a> <a href="index.htm#Macros">Macros</a> <a href="index.htm#Headers">Headers</a>
+<a href="if.htm">Prev</a> <a href="limits.htm">Next</a> <a href="index.htm#Macros">Macros</a> <a href="index.htm#Headers">Headers</a>
 <hr>
 
 <h1>#include &lt;<a href="../../../../boost/preprocessor/inc.hpp">boost/preprocessor/inc.hpp</a>&gt;</h1>
@@ -44,7 +44,7 @@ supported.</p>
  <p>Obsolete. Use <a href="inc.htm#BOOST_PP_INC">BOOST_PP_INC</a>().</p> 
 <hr>
 
-<a href="if_then.htm">Prev</a> <a href="limits.htm">Next</a> <a href="index.htm#Macros">Macros</a> <a href="index.htm#Headers">Headers</a>
+<a href="if.htm">Prev</a> <a href="limits.htm">Next</a> <a href="index.htm#Macros">Macros</a> <a href="index.htm#Headers">Headers</a>
 <hr>
 
 <p>Revised <!--webbot bot="Timestamp" s-type="EDITED" s-format="%d %b %Y" startspan --><!--webbot bot="Timestamp" endspan i-checksum="15246" --></p>
diff --git a/doc/reference/index.htm b/doc/reference/index.htm
index 2dde07f..2980348 100644
--- a/doc/reference/index.htm
+++ b/doc/reference/index.htm
@@ -42,6 +42,7 @@
   <dt><a href="comparison_equal.htm#BOOST_PP_EQUAL">BOOST_PP_EQUAL</a></dt>
   <dt><a href="comparison_equal.htm#BOOST_PP_EQUAL_D">BOOST_PP_EQUAL_D</a></dt>
   <dt><a href="expand.htm#BOOST_PP_EXPAND">BOOST_PP_EXPAND</a></dt>
+  <dt><a href="expr_if.htm#BOOST_PP_EXPR_IF">BOOST_PP_EXPR_IF</a></dt>
   <dt><a href="for.htm#BOOST_PP_FOR">BOOST_PP_FOR</a></dt>
   <dt><a href="comparison_greater.htm#BOOST_PP_GREATER">BOOST_PP_GREATER</a></dt>
   <dt><a href="comparison_greater.htm#BOOST_PP_GREATER_D">BOOST_PP_GREATER_D</a></dt>
@@ -49,7 +50,6 @@
   <dt><a href="comparison_greater_equal.htm#BOOST_PP_GREATER_EQUAL_D">BOOST_PP_GREATER_EQUAL_D</a></dt>
   <dt><a href="identity.htm#BOOST_PP_IDENTITY">BOOST_PP_IDENTITY</a></dt>
   <dt><a href="if.htm#BOOST_PP_IF">BOOST_PP_IF</a></dt>
-  <dt><a href="if_then.htm#BOOST_PP_IF_THEN">BOOST_PP_IF_THEN</a></dt>
   <dt><a href="inc.htm#BOOST_PP_INC">BOOST_PP_INC</a></dt>
   <dt><a href="comparison_less.htm#BOOST_PP_LESS">BOOST_PP_LESS</a></dt>
   <dt><a href="comparison_less.htm#BOOST_PP_LESS_D">BOOST_PP_LESS_D</a></dt>
@@ -197,10 +197,10 @@
   <dt>#include &lt;<a href="enum_shifted.htm">boost/preprocessor/enum_shifted.hpp</a>&gt;</dt>
   <dt>#include &lt;<a href="enum_shifted_params.htm">boost/preprocessor/enum_shifted_params.hpp</a>&gt;</dt>
   <dt>#include &lt;<a href="expand.htm">boost/preprocessor/expand.hpp</a>&gt;</dt>
+  <dt>#include &lt;<a href="expr_if.htm">boost/preprocessor/expr_if.hpp</a>&gt;</dt>
   <dt>#include &lt;<a href="for.htm">boost/preprocessor/for.hpp</a>&gt;</dt>
   <dt>#include &lt;<a href="identity.htm">boost/preprocessor/identity.hpp</a>&gt;</dt>
   <dt>#include &lt;<a href="if.htm">boost/preprocessor/if.hpp</a>&gt;</dt>
-  <dt>#include &lt;<a href="if_then.htm">boost/preprocessor/if_then.hpp</a>&gt;</dt>
   <dt>#include &lt;<a href="inc.htm">boost/preprocessor/inc.hpp</a>&gt;</dt>
   <dt>#include &lt;<a href="limits.htm">boost/preprocessor/limits.hpp</a>&gt;</dt>
   <dt>#include &lt;<a href="list.htm">boost/preprocessor/list.hpp</a>&gt;</dt>
diff --git a/include/boost/preprocessor/assert_msg.hpp b/include/boost/preprocessor/assert_msg.hpp
index 37ecff7..5838683 100644
--- a/include/boost/preprocessor/assert_msg.hpp
+++ b/include/boost/preprocessor/assert_msg.hpp
@@ -13,7 +13,7 @@
  * See http://www.boost.org for most recent version.
  */
 
-#include <boost/preprocessor/if_then.hpp>
+#include <boost/preprocessor/expr_if.hpp>
 #include <boost/preprocessor/logical/not.hpp>
 
 /** <p>Expands to nothing if <code>C != 0</code> and to <code>MSG</code> if
@@ -21,7 +21,7 @@
 
 <p>For example, <code>BOOST_PP_ASSERT_MSG(1,A BUG!)</code> expands to <code>A BUG!</code>.</p>
 */
-#define BOOST_PP_ASSERT_MSG(C,MSG) BOOST_PP_IF_THEN(BOOST_PP_NOT(C),MSG)
+#define BOOST_PP_ASSERT_MSG(C,MSG) BOOST_PP_EXPR_IF(BOOST_PP_NOT(C),MSG)
 
 /** <p>Obsolete. Use BOOST_PP_ASSERT_MSG().</p> */
 #define BOOST_PREPROCESSOR_ASSERT_MSG(C,MSG) BOOST_PP_ASSERT_MSG(C,MSG)
diff --git a/include/boost/preprocessor/expr_if.hpp b/include/boost/preprocessor/expr_if.hpp
new file mode 100644
index 0000000..eb99a10
--- /dev/null
+++ b/include/boost/preprocessor/expr_if.hpp
@@ -0,0 +1,33 @@
+#ifndef BOOST_PREPROCESSOR_EXPR_IF_HPP
+#define BOOST_PREPROCESSOR_EXPR_IF_HPP
+
+/* Copyright (C) 2002
+ * Housemarque Oy
+ * http://www.housemarque.com
+ *
+ * Permission to copy, use, modify, sell and distribute this software is
+ * granted provided this copyright notice appears in all copies. This
+ * software is provided "as is" without express or implied warranty, and
+ * with no claim as to its suitability for any purpose.
+ *
+ * See http://www.boost.org for most recent version.
+ */
+
+#include <boost/preprocessor/logical/bool.hpp>
+
+/** <p>Expands to <code>E</code> if <code>C != 0</code> and to nothing if <code>C == 0</code>.</p>
+
+<p>For example, <code>BOOST_PP_EXPR_IF(1,^)</code> expands to <code>^</code>.</p>
+
+<h3>See</h3>
+<ul>
+  <li>BOOST_PP_IF()</li>
+</ul>
+*/
+#define BOOST_PP_EXPR_IF(C,E) BOOST_PP_EXPR_IF_BOOL(BOOST_PP_BOOL(C),E)
+
+#define BOOST_PP_EXPR_IF_BOOL(C,E) BOOST_PP_EXPR_IF_BOOL_DELAY(C,E)
+#define BOOST_PP_EXPR_IF_BOOL_DELAY(C,E) BOOST_PP_EXPR_IF_BOOL##C(E)
+#define BOOST_PP_EXPR_IF_BOOL0(E)
+#define BOOST_PP_EXPR_IF_BOOL1(E) E
+#endif
diff --git a/include/boost/preprocessor/if.hpp b/include/boost/preprocessor/if.hpp
index 1bce470..158cbf3 100644
--- a/include/boost/preprocessor/if.hpp
+++ b/include/boost/preprocessor/if.hpp
@@ -21,6 +21,11 @@
 
 <p>For example, <code>BOOST_PP_IF(0,1,2)</code> expands to <code>2</code>.</p>
 
+<h3>See</h3>
+<ul>
+  <li>BOOST_PP_EXPR_IF()</li>
+</ul>
+
 <h3>Test</h3>
 <ul>
   <li><a href="../../test/preprocessor_test.cpp">preprocessor_test.cpp</a></li>
diff --git a/include/boost/preprocessor/if_then.hpp b/include/boost/preprocessor/if_then.hpp
deleted file mode 100644
index a850d81..0000000
--- a/include/boost/preprocessor/if_then.hpp
+++ /dev/null
@@ -1,28 +0,0 @@
-#ifndef BOOST_PREPROCESSOR_IF_THEN_HPP
-#define BOOST_PREPROCESSOR_IF_THEN_HPP
-
-/* Copyright (C) 2002
- * Housemarque Oy
- * http://www.housemarque.com
- *
- * Permission to copy, use, modify, sell and distribute this software is
- * granted provided this copyright notice appears in all copies. This
- * software is provided "as is" without express or implied warranty, and
- * with no claim as to its suitability for any purpose.
- *
- * See http://www.boost.org for most recent version.
- */
-
-#include <boost/preprocessor/logical/bool.hpp>
-
-/** <p>Expands to <code>T</code> if <code>C != 0</code> and to nothing if <code>C == 0</code>.</p>
-
-<p>For example, <code>BOOST_PP_IF_THEN(1,^)</code> expands to <code>^</code>.</p>
-*/
-#define BOOST_PP_IF_THEN(C,T) BOOST_PP_IF_THEN_BOOL(BOOST_PP_BOOL(C),T)
-
-#define BOOST_PP_IF_THEN_BOOL(C,T) BOOST_PP_IF_THEN_BOOL_DELAY(C,T)
-#define BOOST_PP_IF_THEN_BOOL_DELAY(C,T) BOOST_PP_IF_THEN_BOOL##C(T)
-#define BOOST_PP_IF_THEN_BOOL0(T)
-#define BOOST_PP_IF_THEN_BOOL1(T) T
-#endif
diff --git a/test/preprocessor_test.cpp b/test/preprocessor_test.cpp
index fe9a0c9..a28690d 100644
--- a/test/preprocessor_test.cpp
+++ b/test/preprocessor_test.cpp
@@ -13,6 +13,7 @@
 #include <boost/preprocessor/empty.hpp>
 #include <boost/preprocessor/identity.hpp>
 #include <boost/preprocessor/if.hpp>
+#include <boost/preprocessor/expr_if.hpp>
 #include <boost/preprocessor/cat.hpp>
 #include <boost/preprocessor/stringize.hpp>
 
@@ -40,6 +41,10 @@ TEST_B BOOST_PP_IF(BOOST_PP_IF(1,1,1),true,false) &&
 
 /* *** */
 
+TEST_B BOOST_PP_EXPR_IF(1,1) TEST_E
+
+/* *** */
+
 #if !(!defined(BOOST_NO_COMPILER_CONFIG) && defined(__MWERKS__))
 TEST_B BOOST_PP_CAT(BOOST_PP_IF(1,tru,fals), MACRO MACRO_ARGS(e)) TEST_E
 #endif