John Vasco has studied the aircraft and operations of the Zerstorergruppen for many years and is the author of several books on the subject including Bombsights Over England - The History of Erprobungsgruppe 210 Luftwaffe Fighter-Bomber Units in the Battle of Britain (1990 and Second edition 2002), Zerstorer: The Messerschmitt 110 and its Units in 1940 ( with Peter D Cornwall - 1995) and The Sting of the Luftwaffe Schnellkampfgeschwader 210 and Zerstorergeschwader 1 in World War 2 (2001). His specialty is the Battle of Britain. He lives in Norfolk, England.