Alan Turing: Unlocking the Enigma

Short, but quite interesting. Such a short book can only give a superficial view of Turing's life and work. Being an computer geek for over 40 years, I've always been interested in Turing. I've seen the reconstructed Colossus at Bletchley Park, although that wasn't his work. So, this has given me the impetus to read a more detailed biography.