It was only in the 1970s that the full story of the German"s Enigma codes used in World War 2 and how the codes were broken by the Allies came to light. Since then the story has been of perennial fascination as it was one of the defining actions of the whole war. Tom Perera is an authority on telecommunications and has been researching this subject for many years. This is the most comprehensive book on the subject ever published, and tells the story of the prewar development of Enigma by Germany, its use during the war, Russian, Swiss, and American versions after the war, the early breakthroughs in intercepting and deciphering the codes by the Poles, and the subsequent collective Allied work in finally cracking the codes concentrated at Bletchley Park.