To celebrate its 60th anniversary circa 1995, Penguin Books released several boxed sets of "Penguin 60s", miniature books about sixty pages in length. The books were also sold individually. The main set, with black spines, (ISBN 0140952721, ISBN 978-0-14-095272-8) contained 60 "classic" works. The UK set with orange spines (ISBN 0140951792 / ISBN 978-0-14-095179-0) focused on 20th century or contemporary writers and contained 60 books. A similar set of 60 orange spine books was released for the American market with 13 books in common with the UK set. Smaller, ten item sets focusing on biography/autobiography, travel and cookery were also issued. A children's set (ISBN 0140953361) was released, consisting of 30 volumes.