Operation Barbarossa the German invasion of the Soviet Union began the largest & most costly campaign in military history. Its failure was a key turning point of the Second World War. The operation was planned as a Blitzkrieg to win Germany its Lebensraum in the east & the summer of 1941 is well-known for the German armys unprecedented victories & advances. Yet the German Blitzkrieg depended almost entirely upon the motorised Panzer groups particularly those of Army Group Centre. Using archival records in this 2009 book David Stahel presents a history of Germanys summer campaign from the perspective of the two largest & most powerful Panzer groups on the Eastern front. Stahels research provides a fundamental reassessment of Germanys war against the Soviet Union highlighting the prodigious internal problems of the vital Panzer forces & revealing that their demise in the earliest phase of the war undermined the whole German invasion.