Train your brain with these fiendishly difficult puzzles, the perfect companion for anyone wanting to keep their mind busy'Fiendishly tricky' Daily MailWith their first bestselling book, The GCHQ Puzzle Book, the UK's intelligence and security experts tested us with puzzles, codes and real-life entrance tests from their archives.
Two Girls, One on Each Knee: A History of Cryptic Crosswords is an audaciously constructed book on the pleasures and puzzles of cryptic crosswords and their linguistic wordplay, from Alan Connor, the Guardian's writer on crosswordsOn 21 December 2013, the crossword puzzle will be 100 years old.
