This book in many places was a long plod through intricacies of mathematics and cryptography with only slight glimpses into the man who was Alan Turing. Persistence will be rewarded, eventually, as the picture of Turing emerges from a tedious chronology-- an incredible genius and worthy of the label "visionary," yet hopelessly naive in the workings of the world, both political and social. He anticipated a universal computer and laid the foundations for artificial intelligence, yet in his later years, he was relegated to a sarcastic footnote in contemporary accounts of the development of the computer.

A reader who dares to attempt this tome surely knows that Alan accepted his homosexuality as a part of his being and that he was crushed by the (conservative) British society he had a significant role in preserving with his code-breaking contributions, particularly in breaking the Enigma encryptions for the Atlantic sea campaigns. The author has made a remarkable effort in assembling from available records this portrait of a complicated man who advanced mathematics and computing, yet tragically was unable to realize all he envisioned.