Singh followed Fermat's Last Theorum with The Code Book, which is an excellent layman's introduction to the fun that can be had with both simple and advanced mathematics. It also contains exercises, puzzles and interesting anecdotes, from cracking heiroglyphics to breaking the Enigma code. The contest, The Code Book Cipher Challenge., reached level 9 of 10 ciphers by Oct. 1st, 2000, giving a prize of a thousand pounds to members of EFF. We have until the year 2010 to crack the last code. (More info can be found at http://www.4thestate.co.uk/cipherchallenge.)

Until just after the publication of The Code Book, Singh wrote a column for UK's Independent on Sunday newspaper. He quit writing this to focus on writing more books, and putting together more documentaries, like...

The Science of Secrecy, another Channel 4 documentary, with accompanying book (published Oct. 4, 2000), this time close to subject of The Code Book. In fact, it pretty much follows the same format, including many of the same anecdotes. Oh well, although treading the same ground, at least it's interesting.