The Defeat of the German U-Boats explains the significance and the outcome of World War II's single most important naval campaign in the European theater—the air and sea battle that ended Germany's bid to sever Allied supply lines in the Atlantic. David Syrett's blow-by-blow recounting of the conflict offers a comprehensive analysis of the effort to stop German U-boat attacks on Allied merchant vessels, which, by 1943, ranked as the Allies' top priority in their strategy to defeat Hitler's forces. Syrett argues that the Germans were unable to match Allied communications, technological, and tactical advances and that the Allies prevailed largely because of their skill in utilizing the material and intelligence resources at their disposal. Beginning with a detailed description of the U-boat's attributes and flaws, Syrett discusses the ship-borne high frequency direction finders, radar, acoustic torpedoes, and improved aircraft developed and deployed by the Allies to stop , German U-boats. He uses Ultra decrypts, or communication intelligence, to plot the progression of each Allied convoy, German U-boat assault, and Allied response. Crediting the Allied victory with keeping Britain in the war and making possible the 1944 invasion of northwest Europe, Syrett emphasizes the pivotal role that the Battle of the Atlantic played in determining World War II's conclusion.