The Battle of the Atlantic and Signals Intelligence: U-boat Situations and Trends, 1941-1945

Contains the weekly series U-boat Situation and the more intermittent bulletin U-boat Trends, written during World War II by Rear Admiral J.W. Clayton and Commander Rodger Winn. These documents relate on a weekly and, in some cases, daily basis, exactly what the British knew concerning the activities of the German U-boats during the Battle of the Atlantic. Circulation was restricted at the Admiralty to the First Lord, the First Sea Lord and perhaps five or six others while at Western Approaches