Walter Schellenberg was a German intelligence officer and diplomat who served as head of the Sicherheitsdienst (SD) and Reichssicherheitshauptamt (RSHA) during the Nazi era. He was a member of the National Socialist Party (NSDAP) and held the rank of SS-Obergruppenführer.
The Enigma of Espionage: Unraveling the Secrets of Walter Schellenberg