Clay Blair’s Hitler's U-Boat War: The Hunters, 1939-1942 is a comprehensive two-volume history utilizing declassified records to examine the German submarine campaign, arguing that Allied anti-submarine efforts made German failure inevitable. The 1996 work details the initial phase of the war, covering U-boat operations against the British Empire and in the Americas, along with technological factors like Enigma. Physical and digital copies of the volume are available through Amazon . Book Review: Hitler's U-boat War, 1939-1942 - HistoryNet