For fifteen years after the end of the war all official Admiralty records For fifteen years after the end of the war all official Admiralty records showed the German submarine U110 as sunk on 9 May 1941 by the surface escorts of convoy OB.318. As this book was the first to reveal, this was a deliberate deception, as the U-boat was actually captured and its contents fully investigated before being allowed to sink a day later, a fact skilfully kept from even the survivors of the submarine's crew. As the official historian of the naval war, Roskill had followed the party line when writing his authorized account, but provoked by exaggerated claims concerning a US Navy capture of a U-boat in 1944, Roskill decided to set the record straight. His narrative is prefaced by brief coverage of previous submarine captures by the Royal Navy ? Three Italian and one German-before covering the U 110 operation in great detail, underlining the skill and bravery of those involved. We now know that the reason for the secrecy was that the U-boat gave up valuable codebooks, charts, ciphers and, most significantly, a complete and undamaged Enigma machine. At the time of the book's first publication, Ultra was still a secret, so Roskill (who clearly knew about it) had to be discreet about the exact details of what was taken from the submarine while insisting on its crucial value to the war effort. However, a new introduction puts the capture into context, making clear its vital importance in the history of allied code-breaking in World War II. AUTHOR: Stephen Roskill, a retired RN captain, was the author of the official history of the Second World War at sea. He later wrote a number of highly regarded books, including a biography of Admiral Beatty and a study of Churchill and the admirals. SELLING POINTS: ? An authoritative account of one of the most significant events of the naval war ? Based on both documentary and eyewitness evidence ? A new introduction places the operation in the wider history of ?Ultra' ILLUSTRATIONS 8 pages of plates *