This book deals with the loss of thirty-five U-boats during the winter of 1943/44. As the season started the large wolf-packs, hunting with their new homing torpedoes, were a force to be reckoned with. But gradually their successes became less and less as the Allies, reading the German naval signals, diverted the convoys around the waiting packs. Many U-boats returned to port with their torpedoes unfired. Early in 1944 the packs were cut down in number. Groups of three, and then later only single boats, were given the task of locating and attacking Atlantic convoys. These thirty-five U-boats, some with very impressive records, were lost either by combined sea and air attacks, by sea-based and land-based aircraft, by striking a mine, or through accidents. United States Navy and Army aircraft registered successes as did American, British and Canadian warships. Giving a balanced view, this book traces the buildup of the wolf-packs as well as their rundown. It contains many fascinating stories, some of which would be considered too outlandish by writers of fiction, yet tell of true incidents involving the roaming wolf-packs.