Karl Dönitz was a German naval officer and politician who, following the suicide of Adolf Hitler during the Second World War in April 1945, succeeded him as head of state of Germany during the Nazi era. He held the position until the dissolution of the Flensburg Government following Germany's unconditional surrender to the Allies weeks later. As Supreme Commander of the Navy beginning in 1943, he played a major role in the naval history of the war.
He began his career in the Imperial German Navy before the First World War. In 1918 he was commanding UB-68, and was captured as a prisoner of war by British forces. As commander of UB-68, he attacked a convoy in the Mediterranean while on patrol near Malta. Sinking one ship before the rest of the convoy outran his U-boat, Dönitz began to formulate the concept of U-boats operating in attack groups Rudeltaktik (German for "pack tactic", commonly called a "wolfpack") for greater efficiency, rather than operating independently.
By the start of the Second World War, Dönitz was supreme commander of the Kriegsmarine's U-boat arm (Befehlshaber der U-Boote [BdU]).