diff -r fceec0368cfa Lib/email/message.py
--- a/Lib/email/message.py	Sun Mar 02 17:14:33 2014 -0500
+++ b/Lib/email/message.py	Mon Mar 03 20:19:17 2014 +0530
@@ -391,17 +391,7 @@
         Note: this does not overwrite an existing header with the same field
         name.  Use __delitem__() first to delete any existing headers.
         """
-        max_count = self.policy.header_max_count(name)
-        if max_count:
-            lname = name.lower()
-            found = 0
-            for k, v in self._headers:
-                if k.lower() == lname:
-                    found += 1
-                    if found >= max_count:
-                        raise ValueError("There may be at most {} {} headers "
-                                         "in a message".format(max_count, name))
-        self._headers.append(self.policy.header_store_parse(name, val))
+        self.set(name, val, pos=len(self)
 
     def __delitem__(self, name):
         """Delete all occurrences of a header, if present.
@@ -466,6 +456,23 @@
                 return self.policy.header_fetch_parse(k, v)
         return failobj
 
+    def set(self, name, val, pos=0):
+        """Set the value of a header.
+
+        Like __setitem__() but sets the value at a given pos location
+        """
+        max_count = self.policy.header_max_count(name)
+        if max_count:
+            lname = name.lower()
+            found = 0
+            for k, v in self._headers:
+                if k.lower() == lname:
+                    found += 1
+                    if found >= max_count:
+                        raise ValueError("There may be at most {} {} headers "
+                                         "in a message".format(max_count, name))
+        self._headers.insert(pos, self.policy.header_store_parse(name, val))
+
     #
     # "Internal" methods (public API, but only intended for use by a parser
     # or generator, not normal application code.
@@ -507,6 +514,19 @@
             return failobj
         return values
 
+    def _parse_values(self, _value, **_params):
+        """Parses the header values as string
+        """
+        parts = []
+        for k, v in _params.items():
+            if v is None:
+                parts.append(k.replace('_', '-'))
+            else:
+                parts.append(_formatparam(k.replace('_', '-'), v))
+        if _value is not None:
+            parts.insert(0, _value)
+        return SEMISPACE.join(parts)
+
     def add_header(self, _name, _value, **_params):
         """Extended header setting.
 
@@ -519,6 +539,8 @@
         encoded according to RFC2231 rules.  Otherwise it will be encoded using
         the utf-8 charset and a language of ''.
 
+        The header is added at the end.
+
         Examples:
 
         msg.add_header('content-disposition', 'attachment', filename='bud.gif')
@@ -527,15 +549,21 @@
         msg.add_header('content-disposition', 'attachment',
                        filename='Fußballer.ppt'))
         """
-        parts = []
-        for k, v in _params.items():
-            if v is None:
-                parts.append(k.replace('_', '-'))
-            else:
-                parts.append(_formatparam(k.replace('_', '-'), v))
-        if _value is not None:
-            parts.insert(0, _value)
-        self[_name] = SEMISPACE.join(parts)
+        self[_name] = self._parse_values(_value, **_params)
+
+    def insert_header(self, _name, _value, **_params):
+        """Extended header settings
+
+        The header is added at the beginning.
+        Message.add_header() explains all other documentation.
+
+        Examples:
+
+        msg.insert_header('content-disposition', 'attachment', filename='bud.gif')
+        msg.insert_header('content-disposition', 'attachment',
+                       filename='Fußballer.ppt'))
+        """
+        self.set(_name, self._parse_values(_value, **_params))
 
     def replace_header(self, _name, _value):
         """Replace a header.