Review : Work it out

David Kahn’s The Codebreakers is the book on codes. Second World War
stories, talking to aliens, and the Rosetta Stone make a stunning thousand-plus
pages of irresistible reading for general readers, specialists and historians.
Now revised, with its new chapter on public key cryptography, it’s even deeply
relevant for Internet users. Published by Simon & Schuster, £45, ISBN
0684831309.