diff --git a/src/calibre/ebooks/metadata/book/render.py b/src/calibre/ebooks/metadata/book/render.py
index 6b4519e2aa..9b648356aa 100644
--- a/src/calibre/ebooks/metadata/book/render.py
+++ b/src/calibre/ebooks/metadata/book/render.py
@@ -6,7 +6,7 @@ from __future__ import (unicode_literals, division, absolute_import,
 __license__ = 'GPL v3'
 __copyright__ = '2014, Kovid Goyal <kovid at kovidgoyal.net>'
 
-import os, cPickle
+import os
 from functools import partial
 from binascii import hexlify
 
@@ -20,6 +20,7 @@ from calibre.utils.icu import sort_key
 from calibre.utils.formatter import EvalFormatter
 from calibre.utils.date import is_date_undefined
 from calibre.utils.localization import calibre_langcode_to_name
+from calibre.utils.serialize import json_dumps
 from polyglot.builtins import unicode_type
 
 default_sort = ('title', 'title_sort', 'authors', 'author_sort', 'series', 'rating', 'pubdate', 'tags', 'publisher', 'identifiers')
@@ -79,7 +80,7 @@ def author_search_href(which, title=None, author=None):
 
 
 def item_data(field_name, value, book_id):
-    return hexlify(cPickle.dumps((field_name, value, book_id), -1))
+    return hexlify(json_dumps((field_name, value, book_id)))
 
 
 def mi_to_html(mi, field_list=None, default_author_link=None, use_roman_numbers=True, rating_font='Liberation Serif', rtl=False):
diff --git a/src/calibre/gui2/book_details.py b/src/calibre/gui2/book_details.py
index af32669c1a..4b97b1d772 100644
--- a/src/calibre/gui2/book_details.py
+++ b/src/calibre/gui2/book_details.py
@@ -2,7 +2,6 @@
 # vim:fileencoding=UTF-8:ts=4:sw=4:sta:et:sts=4:ai
 # License: GPLv3 Copyright: 2010, Kovid Goyal <kovid at kovidgoyal.net>
 
-import cPickle
 import os
 import re
 from binascii import unhexlify
@@ -34,6 +33,7 @@ from calibre.gui2.dnd import (
 from calibre.utils.config import tweaks
 from calibre.utils.img import blend_image, image_from_x
 from calibre.utils.localization import is_rtl
+from calibre.utils.serialize import json_loads
 from polyglot.builtins import unicode_type
 
 _css = None
@@ -286,7 +286,7 @@ def details_context_menu_event(view, ev, book_info):  # {{{
                                    lambda : book_info.search_requested('authors:"={}"'.format(author.replace('"', r'\"'))))
             if data:
                 try:
-                    field, value, book_id = cPickle.loads(unhexlify(data))
+                    field, value, book_id = json_loads(unhexlify(data))
                 except Exception:
                     field = value = book_id = None
                 if field: