Among the famous battles of World War II, the longest and most critical was the Battle of the Atlantic - the struggle between the American convoys bringing supplies to Britain and the German U-boats bent on severing that lifeline. No matter where else on earth conflicts raged, leaders on both sides understood that whoever won the Battle of the Atlantic would win the war. From the start, Germany had the advantage with the diabolically devised encryption machine known as Enigma. Breaking the Enigma codes became the singleminded obsession of a brilliant band of mathematicians, chess champions, and linguists who labored on behalf of the Allied cause behind closed doors at an English estate called Bletchley Park. In this book, cryptologist David Kahn recounts the story of the dramatic race between codemakers and codebreakers, focusing on the personalities involved, describing the at-sea captures of encryption keys that led to the Allied breakthrough, and depicting the enormous impact this information had on the most cataclysmic war in history. B and u0026W photos.