diff --git a/include/boost/unordered/unordered_map_fwd.hpp b/include/boost/unordered/unordered_map_fwd.hpp
new file mode 100644
index 00000000..ceb77fc0
--- /dev/null
+++ b/include/boost/unordered/unordered_map_fwd.hpp
@@ -0,0 +1,53 @@
+
+// Copyright (C) 2008 Daniel James.
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+
+#ifndef BOOST_UNORDERED_MAP_FWD_HPP_INCLUDED
+#define BOOST_UNORDERED_MAP_FWD_HPP_INCLUDED
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1020)
+# pragma once
+#endif
+
+#include <boost/config.hpp>
+#include <memory>
+#include <functional>
+#include <boost/functional/hash_fwd.hpp>
+
+namespace boost
+{
+    template <class Key,
+        class T,
+        class Hash = hash<Key>,
+        class Pred = std::equal_to<Key>,
+        class Alloc = std::allocator<std::pair<const Key, T> > >
+    class unordered_map;
+    template <class K, class T, class H, class P, class A>
+    bool operator==(unordered_map<K, T, H, P, A> const&,
+        unordered_map<K, T, H, P, A> const&);
+    template <class K, class T, class H, class P, class A>
+    bool operator!=(unordered_map<K, T, H, P, A> const&,
+        unordered_map<K, T, H, P, A> const&);
+    template <class K, class T, class H, class P, class A>
+    void swap(unordered_map<K, T, H, P, A>&,
+            unordered_map<K, T, H, P, A>&);
+
+    template <class Key,
+        class T,
+        class Hash = hash<Key>,
+        class Pred = std::equal_to<Key>,
+        class Alloc = std::allocator<std::pair<const Key, T> > >
+    class unordered_multimap;
+    template <class K, class T, class H, class P, class A>
+    bool operator==(unordered_multimap<K, T, H, P, A> const&,
+        unordered_multimap<K, T, H, P, A> const&);
+    template <class K, class T, class H, class P, class A>
+    bool operator!=(unordered_multimap<K, T, H, P, A> const&,
+        unordered_multimap<K, T, H, P, A> const&);
+    template <class K, class T, class H, class P, class A>
+    void swap(unordered_multimap<K, T, H, P, A>&,
+            unordered_multimap<K, T, H, P, A>&);
+}
+
+#endif
diff --git a/include/boost/unordered/unordered_set_fwd.hpp b/include/boost/unordered/unordered_set_fwd.hpp
new file mode 100644
index 00000000..48a2caac
--- /dev/null
+++ b/include/boost/unordered/unordered_set_fwd.hpp
@@ -0,0 +1,51 @@
+
+// Copyright (C) 2008 Daniel James.
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+
+#ifndef BOOST_UNORDERED_SET_FWD_HPP_INCLUDED
+#define BOOST_UNORDERED_SET_FWD_HPP_INCLUDED
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1020)
+# pragma once
+#endif
+
+#include <boost/config.hpp>
+#include <memory>
+#include <functional>
+#include <boost/functional/hash_fwd.hpp>
+
+namespace boost
+{
+    template <class Value,
+        class Hash = hash<Value>,
+        class Pred = std::equal_to<Value>,
+        class Alloc = std::allocator<Value> >
+    class unordered_set;
+    template <class T, class H, class P, class A>
+    bool operator==(unordered_set<T, H, P, A> const&,
+        unordered_set<T, H, P, A> const&);
+    template <class T, class H, class P, class A>
+    bool operator!=(unordered_set<T, H, P, A> const&,
+        unordered_set<T, H, P, A> const&);
+    template <class T, class H, class P, class A>
+    void swap(unordered_set<T, H, P, A> &m1,
+            unordered_set<T, H, P, A> &m2);
+
+    template <class Value,
+        class Hash = hash<Value>,
+        class Pred = std::equal_to<Value>,
+        class Alloc = std::allocator<Value> >
+    class unordered_multiset;
+    template <class T, class H, class P, class A>
+    bool operator==(unordered_multiset<T, H, P, A> const&,
+        unordered_multiset<T, H, P, A> const&);
+    template <class T, class H, class P, class A>
+    bool operator!=(unordered_multiset<T, H, P, A> const&,
+        unordered_multiset<T, H, P, A> const&);
+    template <class T, class H, class P, class A>
+    void swap(unordered_multiset<T, H, P, A> &m1,
+            unordered_multiset<T, H, P, A> &m2);
+}
+
+#endif
diff --git a/include/boost/unordered_map.hpp b/include/boost/unordered_map.hpp
index d675f07a..f4593517 100644
--- a/include/boost/unordered_map.hpp
+++ b/include/boost/unordered_map.hpp
@@ -13,11 +13,7 @@
 # pragma once
 #endif
 
-#include <boost/config.hpp>
-
-#include <functional>
-#include <memory>
-
+#include <boost/unordered/unordered_map_fwd.hpp>
 #include <boost/functional/hash.hpp>
 #include <boost/unordered/detail/hash_table.hpp>
 
@@ -27,38 +23,6 @@
 
 namespace boost
 {
-    template <class Key,
-        class T,
-        class Hash = hash<Key>,
-        class Pred = std::equal_to<Key>,
-        class Alloc = std::allocator<std::pair<const Key, T> > >
-    class unordered_map;
-    template <class K, class T, class H, class P, class A>
-    bool operator==(unordered_map<K, T, H, P, A> const&,
-        unordered_map<K, T, H, P, A> const&);
-    template <class K, class T, class H, class P, class A>
-    bool operator!=(unordered_map<K, T, H, P, A> const&,
-        unordered_map<K, T, H, P, A> const&);
-    template <class K, class T, class H, class P, class A>
-    void swap(unordered_map<K, T, H, P, A>&,
-            unordered_map<K, T, H, P, A>&);
-
-    template <class Key,
-        class T,
-        class Hash = hash<Key>,
-        class Pred = std::equal_to<Key>,
-        class Alloc = std::allocator<std::pair<const Key, T> > >
-    class unordered_multimap;
-    template <class K, class T, class H, class P, class A>
-    bool operator==(unordered_multimap<K, T, H, P, A> const&,
-        unordered_multimap<K, T, H, P, A> const&);
-    template <class K, class T, class H, class P, class A>
-    bool operator!=(unordered_multimap<K, T, H, P, A> const&,
-        unordered_multimap<K, T, H, P, A> const&);
-    template <class K, class T, class H, class P, class A>
-    void swap(unordered_multimap<K, T, H, P, A>&,
-            unordered_multimap<K, T, H, P, A>&);
-
     template <class Key, class T, class Hash, class Pred, class Alloc>
     class unordered_map
     {
diff --git a/include/boost/unordered_set.hpp b/include/boost/unordered_set.hpp
index 4b850685..9e4f12b4 100644
--- a/include/boost/unordered_set.hpp
+++ b/include/boost/unordered_set.hpp
@@ -13,11 +13,7 @@
 # pragma once
 #endif
 
-#include <boost/config.hpp>
-
-#include <functional>
-#include <memory>
-
+#include <boost/unordered/unordered_set_fwd.hpp>
 #include <boost/functional/hash.hpp>
 #include <boost/unordered/detail/hash_table.hpp>
 
@@ -27,36 +23,6 @@
 
 namespace boost
 {
-    template <class Value,
-        class Hash = hash<Value>,
-        class Pred = std::equal_to<Value>,
-        class Alloc = std::allocator<Value> >
-    class unordered_set;
-    template <class T, class H, class P, class A>
-    bool operator==(unordered_set<T, H, P, A> const&,
-        unordered_set<T, H, P, A> const&);
-    template <class T, class H, class P, class A>
-    bool operator!=(unordered_set<T, H, P, A> const&,
-        unordered_set<T, H, P, A> const&);
-    template <class T, class H, class P, class A>
-    void swap(unordered_set<T, H, P, A> &m1,
-            unordered_set<T, H, P, A> &m2);
-
-    template <class Value,
-        class Hash = hash<Value>,
-        class Pred = std::equal_to<Value>,
-        class Alloc = std::allocator<Value> >
-    class unordered_multiset;
-    template <class T, class H, class P, class A>
-    bool operator==(unordered_multiset<T, H, P, A> const&,
-        unordered_multiset<T, H, P, A> const&);
-    template <class T, class H, class P, class A>
-    bool operator!=(unordered_multiset<T, H, P, A> const&,
-        unordered_multiset<T, H, P, A> const&);
-    template <class T, class H, class P, class A>
-    void swap(unordered_multiset<T, H, P, A> &m1,
-            unordered_multiset<T, H, P, A> &m2);
-
     template <class Value, class Hash, class Pred, class Alloc>
     class unordered_set
     {
diff --git a/test/unordered/Jamfile.v2 b/test/unordered/Jamfile.v2
index d913e8e8..9ecec284 100644
--- a/test/unordered/Jamfile.v2
+++ b/test/unordered/Jamfile.v2
@@ -14,6 +14,8 @@ project unordered-test/unordered
 
 test-suite unordered
     :
+        [ run fwd_set_test.cpp ]
+        [ run fwd_map_test.cpp ]
         [ run compile_set.cpp ]
         [ run compile_map.cpp ]
         [ run link_test_1.cpp link_test_2.cpp ]
diff --git a/test/unordered/fwd_map_test.cpp b/test/unordered/fwd_map_test.cpp
new file mode 100644
index 00000000..a0d118e5
--- /dev/null
+++ b/test/unordered/fwd_map_test.cpp
@@ -0,0 +1,62 @@
+
+// Copyright 2008 Daniel James.
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+
+#include <boost/unordered/unordered_map_fwd.hpp>
+
+typedef boost::unordered_map<int, int> int_map;
+
+void call_swap(int_map& x, int_map& y) {
+    swap(x,y);
+}
+
+bool call_equals(int_map& x, int_map& y) {
+    return x == y;
+}
+
+bool call_not_equals(int_map& x, int_map& y) {
+    return x != y;
+}
+
+typedef boost::unordered_multimap<int, int> int_multimap;
+
+void call_swap(int_multimap& x, int_multimap& y) {
+    swap(x,y);
+}
+
+bool call_equals(int_multimap& x, int_multimap& y) {
+    return x == y;
+}
+
+bool call_not_equals(int_multimap& x, int_multimap& y) {
+    return x != y;
+}
+
+#include <boost/unordered_map.hpp>
+#include "../helpers/test.hpp"
+
+UNORDERED_AUTO_TEST(use_map_fwd_declared_function) {
+    int_map x, y;
+    x[1] = 2;
+    y[2] = 1;
+    call_swap(x, y);
+
+    BOOST_CHECK(y.find(1) != y.end() && y.find(1)->second == 2);
+    BOOST_CHECK(y.find(2) == y.end());
+
+    BOOST_CHECK(x.find(1) == x.end());
+    BOOST_CHECK(x.find(2) != x.end() && x.find(2)->second == 1);
+
+    BOOST_CHECK(!call_equals(x, y));
+    BOOST_CHECK(call_not_equals(x, y));
+}
+
+UNORDERED_AUTO_TEST(use_multimap_fwd_declared_function) {
+    int_multimap x, y;
+    call_swap(x, y);
+    BOOST_CHECK(call_equals(x, y));
+    BOOST_CHECK(!call_not_equals(x, y));
+}
+
+RUN_TESTS()
diff --git a/test/unordered/fwd_set_test.cpp b/test/unordered/fwd_set_test.cpp
new file mode 100644
index 00000000..3b39f8b3
--- /dev/null
+++ b/test/unordered/fwd_set_test.cpp
@@ -0,0 +1,84 @@
+
+// Copyright 2008 Daniel James.
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+
+#include <boost/unordered/unordered_set_fwd.hpp>
+
+struct true_type { char x[100]; };
+struct false_type { char x; };
+
+false_type is_unordered_set_impl(void*);
+
+template <class Value, class Hash, class Pred, class Alloc>
+true_type is_unordered_set_impl(
+        boost::unordered_set<Value, Hash, Pred, Alloc>*);
+
+typedef boost::unordered_set<int> int_set;
+
+void call_swap(int_set& x, int_set& y) {
+    swap(x,y);
+}
+
+bool call_equals(int_set& x, int_set& y) {
+    return x == y;
+}
+
+bool call_not_equals(int_set& x, int_set& y) {
+    return x != y;
+}
+
+typedef boost::unordered_multiset<int> int_multiset;
+
+void call_swap(int_multiset& x, int_multiset& y) {
+    swap(x,y);
+}
+
+bool call_equals(int_multiset& x, int_multiset& y) {
+    return x == y;
+}
+
+bool call_not_equals(int_multiset& x, int_multiset& y) {
+    return x != y;
+}
+
+#include "../helpers/test.hpp"
+
+UNORDERED_AUTO_TEST(use_fwd_declared_trait_without_definition) {
+    BOOST_CHECK(sizeof(is_unordered_set_impl((int_set*) 0)) == sizeof(true_type));
+}
+
+#include <boost/unordered_set.hpp>
+
+UNORDERED_AUTO_TEST(use_fwd_declared_trait) {
+    boost::unordered_set<int> x;
+    BOOST_CHECK(sizeof(is_unordered_set_impl(&x)) == sizeof(true_type));
+
+    int dummy;
+    BOOST_CHECK(sizeof(is_unordered_set_impl(&dummy)) == sizeof(false_type));
+}
+
+UNORDERED_AUTO_TEST(use_set_fwd_declared_function) {
+    int_set x, y;
+    x.insert(1);
+    y.insert(2);
+    call_swap(x, y);
+
+    BOOST_CHECK(y.find(1) != y.end());
+    BOOST_CHECK(y.find(2) == y.end());
+
+    BOOST_CHECK(x.find(1) == x.end());
+    BOOST_CHECK(x.find(2) != x.end());
+
+    BOOST_CHECK(!call_equals(x, y));
+    BOOST_CHECK(call_not_equals(x, y));
+}
+
+UNORDERED_AUTO_TEST(use_multiset_fwd_declared_function) {
+    int_multiset x, y;
+    call_swap(x, y);
+    BOOST_CHECK(call_equals(x, y));
+    BOOST_CHECK(!call_not_equals(x, y));
+}
+
+RUN_TESTS()