The story of the fighting of German submarines in World War II is a drama with ups and downs and again with new ups. German submarine forces revived from the ashes to become the Third Reich's most effective means of fighting the West. In a few short months, the U-bots seemed to gain the upper hand in the Battle of the Atlantic, slowly but surely bringing England to its knees until, in May 1943, the shifting fortune turned away, bringing the bitterness of a lost struggle against a materially superior enemy with an extreme lack of its resources.