為一著名軍事歷史學者，擔任軍事出版品寫作及顧問已達25年。主要作品有：
German campaigns of World War II
The Rise of Hitler’s Third Reich
SS: Hitler’s Foreign Divisions
The Essential Tank Identification Guide: Wehrmacht Panzer Divisions,1939-45
The Essential Airkraft Identification Guide: Luftwaffe Squadrons,1939-45
The Essential Vehicle Identification Guide: Panzergrenadier Divisions,1939-45
