In May 1943, Allied sea and air forces won a stunning, dramatic, and vital victory over the largest and most powerful submarine force ever sent to sea, sinking forty-one German U-boats and damaging thirty-seven others. It was the forty-fifth month of World War II, and by the end of May the Germans were forced to acknowledge defeat and recall almost all of their remaining U-boats from the major traffic lanes of the North Atlantic. At U-Boat Headquarters in Berlin, despondent naval officers spoke of "Black May." It was a defeat from which the German U-boat fleet never recovered.Black May is a triumph of scholarship and narrative, an important work of history, and a great sea story. Acclaimed historian Michael Gannon, author of Operation Drumbeat, has done enormous research and produced the most thoroughly documented study ever done of these battles. In his compelling historical saga...