diff --git a/erb/cpp03_define.hpp.erb b/erb/cpp03_define.hpp.erb
index d52f8dda..45a72f93 100644
--- a/erb/cpp03_define.hpp.erb
+++ b/erb/cpp03_define.hpp.erb
@@ -19,7 +19,8 @@
 #define MSGPACK_CPP03_DEFINE_HPP
 
 #include "msgpack/versioning.hpp"
-#include "msgpack_fwd.hpp"
+#include "msgpack/adaptor/msgpack_tuple_fwd.hpp"
+#include "msgpack/object_fwd.hpp"
 
 #define MSGPACK_DEFINE(...) \
     template <typename Packer> \
diff --git a/erb/cpp03_msgpack_tuple.hpp.erb b/erb/cpp03_msgpack_tuple.hpp.erb
index a355dd77..9f3534a8 100644
--- a/erb/cpp03_msgpack_tuple.hpp.erb
+++ b/erb/cpp03_msgpack_tuple.hpp.erb
@@ -19,7 +19,7 @@
 #define MSGPACK_CPP03_MSGPACK_TUPLE_HPP
 
 #include "msgpack/versioning.hpp"
-#include "msgpack_fwd.hpp"
+#include "msgpack/object.hpp"
 
 namespace msgpack {
 
diff --git a/erb/cpp03_zone.hpp.erb b/erb/cpp03_zone.hpp.erb
index ed4d263e..9b16bb65 100644
--- a/erb/cpp03_zone.hpp.erb
+++ b/erb/cpp03_zone.hpp.erb
@@ -23,7 +23,6 @@
 #include <vector>
 
 #include "msgpack/versioning.hpp"
-#include "msgpack_fwd.hpp"
 
 #ifndef MSGPACK_ZONE_CHUNK_SIZE
 #define MSGPACK_ZONE_CHUNK_SIZE 8192
diff --git a/include/msgpack/adaptor/bool.hpp b/include/msgpack/adaptor/bool.hpp
index 5194b828..df7e7ac7 100644
--- a/include/msgpack/adaptor/bool.hpp
+++ b/include/msgpack/adaptor/bool.hpp
@@ -19,7 +19,7 @@
 #define MSGPACK_TYPE_BOOL_HPP
 
 #include "msgpack/versioning.hpp"
-#include "msgpack_fwd.hpp"
+#include "msgpack/object_fwd.hpp"
 #include <vector>
 
 namespace msgpack {
diff --git a/include/msgpack/adaptor/char_ptr.hpp b/include/msgpack/adaptor/char_ptr.hpp
index c1071462..dca1acff 100644
--- a/include/msgpack/adaptor/char_ptr.hpp
+++ b/include/msgpack/adaptor/char_ptr.hpp
@@ -19,7 +19,7 @@
 #define MSGPACK_TYPE_CHAR_PTR_HPP
 
 #include "msgpack/versioning.hpp"
-#include "msgpack_fwd.hpp"
+#include "msgpack/object_fwd.hpp"
 #include <cstring>
 
 namespace msgpack {
diff --git a/include/msgpack/adaptor/cpp11/array.hpp b/include/msgpack/adaptor/cpp11/array.hpp
index 573ff2d2..6c932adf 100644
--- a/include/msgpack/adaptor/cpp11/array.hpp
+++ b/include/msgpack/adaptor/cpp11/array.hpp
@@ -20,7 +20,7 @@
 #define MSGPACK_CPP11_ARRAY_HPP
 
 #include "msgpack/versioning.hpp"
-#include "msgpack_fwd.hpp"
+#include "msgpack/object_fwd.hpp"
 
 #include <array>
 
diff --git a/include/msgpack/adaptor/cpp11/forward_list.hpp b/include/msgpack/adaptor/cpp11/forward_list.hpp
index 6f52365d..dd78afd6 100644
--- a/include/msgpack/adaptor/cpp11/forward_list.hpp
+++ b/include/msgpack/adaptor/cpp11/forward_list.hpp
@@ -20,7 +20,7 @@
 #define MSGPACK_CPP11_FORWARD_LIST_HPP
 
 #include "msgpack/versioning.hpp"
-#include "msgpack_fwd.hpp"
+#include "msgpack/object_fwd.hpp"
 
 #include <forward_list>
 
diff --git a/include/msgpack/adaptor/cpp11/tuple.hpp b/include/msgpack/adaptor/cpp11/tuple.hpp
index 0e1a03cd..b917360a 100644
--- a/include/msgpack/adaptor/cpp11/tuple.hpp
+++ b/include/msgpack/adaptor/cpp11/tuple.hpp
@@ -19,7 +19,7 @@
 #define MSGPACK_CPP11_TUPLE_HPP
 
 #include "msgpack/versioning.hpp"
-#include "msgpack_fwd.hpp"
+#include "msgpack/object_fwd.hpp"
 
 #include <tuple>
 
diff --git a/include/msgpack/adaptor/deque.hpp b/include/msgpack/adaptor/deque.hpp
index fc0bbbf7..94bac923 100644
--- a/include/msgpack/adaptor/deque.hpp
+++ b/include/msgpack/adaptor/deque.hpp
@@ -19,7 +19,7 @@
 #define MSGPACK_TYPE_DEQUE_HPP
 
 #include "msgpack/versioning.hpp"
-#include "msgpack_fwd.hpp"
+#include "msgpack/object_fwd.hpp"
 #include <deque>
 
 namespace msgpack {
diff --git a/include/msgpack/adaptor/detail/cpp03_define.hpp b/include/msgpack/adaptor/detail/cpp03_define.hpp
index 442837cb..3673da88 100644
--- a/include/msgpack/adaptor/detail/cpp03_define.hpp
+++ b/include/msgpack/adaptor/detail/cpp03_define.hpp
@@ -19,7 +19,8 @@
 #define MSGPACK_CPP03_DEFINE_HPP
 
 #include "msgpack/versioning.hpp"
-#include "msgpack_fwd.hpp"
+#include "msgpack/adaptor/msgpack_tuple_fwd.hpp"
+#include "msgpack/object_fwd.hpp"
 
 #define MSGPACK_DEFINE(...) \
     template <typename Packer> \
diff --git a/include/msgpack/adaptor/detail/cpp03_msgpack_tuple.hpp b/include/msgpack/adaptor/detail/cpp03_msgpack_tuple.hpp
index 7b9b29a1..70346189 100644
--- a/include/msgpack/adaptor/detail/cpp03_msgpack_tuple.hpp
+++ b/include/msgpack/adaptor/detail/cpp03_msgpack_tuple.hpp
@@ -19,7 +19,7 @@
 #define MSGPACK_CPP03_MSGPACK_TUPLE_HPP
 
 #include "msgpack/versioning.hpp"
-#include "msgpack_fwd.hpp"
+#include "msgpack/object.hpp"
 
 namespace msgpack {
 
diff --git a/include/msgpack/adaptor/detail/cpp11_define.hpp b/include/msgpack/adaptor/detail/cpp11_define.hpp
index 1953d4b4..6e29b4ad 100644
--- a/include/msgpack/adaptor/detail/cpp11_define.hpp
+++ b/include/msgpack/adaptor/detail/cpp11_define.hpp
@@ -19,7 +19,7 @@
 #define MSGPACK_CPP11_DEFINE_HPP
 
 #include "msgpack/versioning.hpp"
-#include "msgpack_fwd.hpp"
+#include "msgpack/object_fwd.hpp"
 
 // for MSGPACK_ADD_ENUM
 #include "msgpack/adaptor/int_fwd.hpp"
diff --git a/include/msgpack/adaptor/detail/cpp11_msgpack_tuple.hpp b/include/msgpack/adaptor/detail/cpp11_msgpack_tuple.hpp
index 9532021d..3b532d87 100644
--- a/include/msgpack/adaptor/detail/cpp11_msgpack_tuple.hpp
+++ b/include/msgpack/adaptor/detail/cpp11_msgpack_tuple.hpp
@@ -19,7 +19,7 @@
 #define MSGPACK_CPP11_MSGPACK_TUPLE_HPP
 
 #include "msgpack/versioning.hpp"
-#include "msgpack_fwd.hpp"
+#include "msgpack/object_fwd.hpp"
 
 #include <tuple>
 
diff --git a/include/msgpack/adaptor/fixint.hpp b/include/msgpack/adaptor/fixint.hpp
index 83a9e95c..eb7f7a8a 100644
--- a/include/msgpack/adaptor/fixint.hpp
+++ b/include/msgpack/adaptor/fixint.hpp
@@ -19,7 +19,7 @@
 #define MSGPACK_TYPE_FIXINT_HPP
 
 #include "msgpack/versioning.hpp"
-#include "msgpack_fwd.hpp"
+#include "msgpack/object_fwd.hpp"
 #include "msgpack/adaptor/int.hpp"
 
 namespace msgpack {
diff --git a/include/msgpack/adaptor/float.hpp b/include/msgpack/adaptor/float.hpp
index 499cbbe0..8191db91 100644
--- a/include/msgpack/adaptor/float.hpp
+++ b/include/msgpack/adaptor/float.hpp
@@ -19,7 +19,7 @@
 #define MSGPACK_TYPE_FLOAT_HPP
 
 #include "msgpack/versioning.hpp"
-#include "msgpack_fwd.hpp"
+#include "msgpack/object_fwd.hpp"
 #include <vector>
 
 namespace msgpack {
diff --git a/include/msgpack/adaptor/list.hpp b/include/msgpack/adaptor/list.hpp
index b185fa24..321f531b 100644
--- a/include/msgpack/adaptor/list.hpp
+++ b/include/msgpack/adaptor/list.hpp
@@ -19,7 +19,7 @@
 #define MSGPACK_TYPE_LIST_HPP
 
 #include "msgpack/versioning.hpp"
-#include "msgpack_fwd.hpp"
+#include "msgpack/object_fwd.hpp"
 #include <list>
 
 namespace msgpack {
diff --git a/include/msgpack/adaptor/map.hpp b/include/msgpack/adaptor/map.hpp
index 16b600d8..c42148e4 100644
--- a/include/msgpack/adaptor/map.hpp
+++ b/include/msgpack/adaptor/map.hpp
@@ -19,7 +19,7 @@
 #define MSGPACK_TYPE_MAP_HPP
 
 #include "msgpack/versioning.hpp"
-#include "msgpack_fwd.hpp"
+#include "msgpack/object_fwd.hpp"
 #include <map>
 #include <vector>
 #include <algorithm>
diff --git a/include/msgpack/adaptor/nil.hpp b/include/msgpack/adaptor/nil.hpp
index 1889307a..4b092e28 100644
--- a/include/msgpack/adaptor/nil.hpp
+++ b/include/msgpack/adaptor/nil.hpp
@@ -19,7 +19,7 @@
 #define MSGPACK_TYPE_NIL_HPP
 
 #include "msgpack/versioning.hpp"
-#include "msgpack_fwd.hpp"
+#include "msgpack/object_fwd.hpp"
 
 namespace msgpack {
 
diff --git a/include/msgpack/adaptor/pair.hpp b/include/msgpack/adaptor/pair.hpp
index 9efc1892..27b88fae 100644
--- a/include/msgpack/adaptor/pair.hpp
+++ b/include/msgpack/adaptor/pair.hpp
@@ -19,7 +19,7 @@
 #define MSGPACK_TYPE_PAIR_HPP
 
 #include "msgpack/versioning.hpp"
-#include "msgpack_fwd.hpp"
+#include "msgpack/object_fwd.hpp"
 #include <utility>
 
 namespace msgpack {
diff --git a/include/msgpack/adaptor/raw.hpp b/include/msgpack/adaptor/raw.hpp
index a01a72c8..590b5de7 100644
--- a/include/msgpack/adaptor/raw.hpp
+++ b/include/msgpack/adaptor/raw.hpp
@@ -19,7 +19,7 @@
 #define MSGPACK_TYPE_RAW_HPP
 
 #include "msgpack/versioning.hpp"
-#include "msgpack_fwd.hpp"
+#include "msgpack/object_fwd.hpp"
 #include <string.h>
 #include <string>
 
diff --git a/include/msgpack/adaptor/set.hpp b/include/msgpack/adaptor/set.hpp
index 2e154fdb..f31169c9 100644
--- a/include/msgpack/adaptor/set.hpp
+++ b/include/msgpack/adaptor/set.hpp
@@ -19,7 +19,7 @@
 #define MSGPACK_TYPE_SET_HPP
 
 #include "msgpack/versioning.hpp"
-#include "msgpack_fwd.hpp"
+#include "msgpack/object_fwd.hpp"
 
 #include <set>
 
diff --git a/include/msgpack/adaptor/string.hpp b/include/msgpack/adaptor/string.hpp
index dd4a37a9..05c2867f 100644
--- a/include/msgpack/adaptor/string.hpp
+++ b/include/msgpack/adaptor/string.hpp
@@ -19,7 +19,7 @@
 #define MSGPACK_TYPE_STRING_HPP
 
 #include "msgpack/versioning.hpp"
-#include "msgpack_fwd.hpp"
+#include "msgpack/object_fwd.hpp"
 #include <string>
 
 namespace msgpack {
diff --git a/include/msgpack/adaptor/tr1/unordered_map.hpp b/include/msgpack/adaptor/tr1/unordered_map.hpp
index de24a11c..7c411cfc 100644
--- a/include/msgpack/adaptor/tr1/unordered_map.hpp
+++ b/include/msgpack/adaptor/tr1/unordered_map.hpp
@@ -19,7 +19,7 @@
 #define MSGPACK_TYPE_TR1_UNORDERED_MAP_HPP
 
 #include "msgpack/versioning.hpp"
-#include "msgpack_fwd.hpp"
+#include "msgpack/object_fwd.hpp"
 
 #if defined(_LIBCPP_VERSION) || (_MSC_VER >= 1700)
 
diff --git a/include/msgpack/adaptor/tr1/unordered_set.hpp b/include/msgpack/adaptor/tr1/unordered_set.hpp
index 928556fb..1d142e6a 100644
--- a/include/msgpack/adaptor/tr1/unordered_set.hpp
+++ b/include/msgpack/adaptor/tr1/unordered_set.hpp
@@ -19,7 +19,7 @@
 #define MSGPACK_TYPE_TR1_UNORDERED_SET_HPP
 
 #include "msgpack/versioning.hpp"
-#include "msgpack_fwd.hpp"
+#include "msgpack/object_fwd.hpp"
 
 #if defined(_LIBCPP_VERSION) || (_MSC_VER >= 1700)
 
diff --git a/include/msgpack/adaptor/vector.hpp b/include/msgpack/adaptor/vector.hpp
index c004d388..fe643117 100644
--- a/include/msgpack/adaptor/vector.hpp
+++ b/include/msgpack/adaptor/vector.hpp
@@ -19,7 +19,7 @@
 #define MSGPACK_TYPE_VECTOR_HPP
 
 #include "msgpack/versioning.hpp"
-#include "msgpack_fwd.hpp"
+#include "msgpack/object_fwd.hpp"
 #include <vector>
 
 namespace msgpack {
diff --git a/include/msgpack/adaptor/vector_char.hpp b/include/msgpack/adaptor/vector_char.hpp
index 225c68ce..1ea6c93c 100644
--- a/include/msgpack/adaptor/vector_char.hpp
+++ b/include/msgpack/adaptor/vector_char.hpp
@@ -19,7 +19,7 @@
 #define MSGPACK_TYPE_VECTOR_CHAR_HPP
 
 #include "msgpack/versioning.hpp"
-#include "msgpack_fwd.hpp"
+#include "msgpack/object_fwd.hpp"
 #include <vector>
 
 namespace msgpack {
diff --git a/include/msgpack/detail/cpp03_zone.hpp b/include/msgpack/detail/cpp03_zone.hpp
index b050a998..8d202232 100644
--- a/include/msgpack/detail/cpp03_zone.hpp
+++ b/include/msgpack/detail/cpp03_zone.hpp
@@ -23,7 +23,6 @@
 #include <vector>
 
 #include "msgpack/versioning.hpp"
-#include "msgpack_fwd.hpp"
 
 #ifndef MSGPACK_ZONE_CHUNK_SIZE
 #define MSGPACK_ZONE_CHUNK_SIZE 8192
diff --git a/include/msgpack/object.hpp b/include/msgpack/object.hpp
index 4be3fca4..b6df9fa5 100644
--- a/include/msgpack/object.hpp
+++ b/include/msgpack/object.hpp
@@ -86,6 +86,36 @@ inline object const& operator>> (object const& o, object& v)
 template <typename T>
 inline object const& operator>> (object const& o, T& v)
 {
+    // If you get a error 'class your_class has no member named 'msgpack_unpack',
+    // check the following:
+    // 1. The class your_class should have MSGPACK_DEFINE macro or
+    //
+    // 2. The class your_class should have the following operator declaration and
+    //    definition:
+    //    inline object const& operator>> (object const& o, std::string& v)
+    //
+    //    See 3.
+    //
+    // 3. #include "msgpack.hpp" too early.
+    //    Replace msgpack.hpp with msgpack_fwd.hpp, then,
+    //    place operator declarations as follows:
+    //
+    //    namespace msgpack {
+    //    MSGPACK_API_VERSION_NAMESPACE(MSGPACK_DEFAULT_API_NS) {
+    //    object const& operator>> (object const& o, std::string& v);
+    //    }
+    //    }
+    //
+    //    then, #include "msgpack.hpp", finally place the operator definitions as follows:
+    //
+    //    namespace msgpack {
+    //    MSGPACK_API_VERSION_NAMESPACE(MSGPACK_DEFAULT_API_NS) {
+    //    object const& operator>> (object const& o, std::string& v) {
+    //        // converting operations here
+    //    }
+    //    } // MSGPACK_API_VERSION_NAMESPACE(MSGPACK_DEFAULT_API_NS)
+    //    } // namespace msgpack
+    //
     v.msgpack_unpack(o.convert());
     return o;
 }
@@ -116,6 +146,42 @@ namespace detail {
 template <typename Stream, typename T>
 struct packer_serializer {
     static packer<Stream>& pack(packer<Stream>& o, const T& v) {
+        // If you get a error 'const class your_class has no member named 'msgpack_pack',
+        // check the following:
+        // 1. The class your_class should have MSGPACK_DEFINE macro or
+        //
+        // 2. The class your_class should have the following operator declaration and
+        //    definition:
+        //
+        //    namespace msgpack {
+        //    MSGPACK_API_VERSION_NAMESPACE(MSGPACK_DEFAULT_API_NS) {
+        //    template <typename Stream>
+        //    inline packer<Stream>& operator<< (packer<Stream>& o, const your_class& v)
+        //    } // MSGPACK_API_VERSION_NAMESPACE(MSGPACK_DEFAULT_API_NS)
+        //    } // namespace msgpack
+        //
+        //    See 3.
+        //
+        // 3. #include "msgpack.hpp" too early.
+        //    Replace msgpack.hpp with msgpack_fwd.hpp, then,
+        //    place operator declarations as follows:
+        //
+        //    namespace msgpack {
+        //    MSGPACK_API_VERSION_NAMESPACE(MSGPACK_DEFAULT_API_NS) {
+        //    template <typename Stream>
+        //    packer<Stream>& operator<< (packer<Stream>& o, const your_class& v);
+        //    } // MSGPACK_API_VERSION_NAMESPACE(MSGPACK_DEFAULT_API_NS)
+        //    } // namespace msgpack
+        //
+        //    then, #include "msgpack.hpp", finally place the operator definitions as follows:
+        //
+        //    template <typename Stream>
+        //    inline packer<Stream>& operator<< (packer<Stream>& o, const your_class& v) {
+        //         // packing operation
+        //    }
+        //    } // MSGPACK_API_VERSION_NAMESPACE(MSGPACK_DEFAULT_API_NS)
+        //    } // namespace msgpack
+        //
         v.msgpack_pack(o);
         return o;
     }
diff --git a/include/msgpack_fwd.hpp b/include/msgpack_fwd.hpp
index 91921dbb..f42ae169 100644
--- a/include/msgpack_fwd.hpp
+++ b/include/msgpack_fwd.hpp
@@ -21,6 +21,7 @@
 #include "msgpack/versioning.hpp"
 #include "msgpack/zone.hpp"
 #include "msgpack/object_fwd.hpp"
+#include "msgpack/adaptor/define.hpp"
 #include "msgpack/pack.hpp"
 
 #endif // MSGPACK_FWD_HPP