A vivid recap of the formidable role played by Nazi Germany's U-boats during WW II; from the industrious Hoyt (America's Wars, p. 836; etc.). In his narrative, which ranges from the unauthorized torpedoing of the passenger liner Athenia by U-30 during the first days of the war through the sinking of U-1195 off the Isle of Wight in 1945, Hoyt makes it abundantly clear that German sub crews gave generally fine accounts of themselves; in fact, the U-boat Korps came close to severing the Allies' vital sealane lifelines. Under the leadership of Admiral Karl Doenitz, lone raiders and so-called wolfpacks achieved stunning tactical triumphs in every theater. Hitler blunted the strategic potential of U-boats, however, by his insistence that they patrol death-trap waters off North Africa and by his reluctance to allocate either manpower or material resources to the underseas service. In the meantime, Hoyt reports, the intuitive Winston Churchill and a tough-minded British naval officer named John Walker were developing anti-submarine measures that put U-boats on the defensive virtually everywhere they operated. Convoy escorts, hunter-killer aircraft, and warships began to exact a terrible toll, thanks to Anglo-American industrial might and technical skills. By the end of 1944 (a year that saw 240 U-boats sent to the bottom), the monthly total of shipping lost to German subs fell below 100,000 tons, against upwards of 700,000 in the better hunting days through 1942. Drawing on a wealth of archival sources, Hoyt offers an anecdotal but comprehensive account of the signal contributions made by U-boats to the German war effort. Dramatically documented and sharply focused, the text has appeal for general readers as well as military-history buffs. There are black-and-white photographs (not seen), plus three helpful maps.