The Origins of Mechanized Warfare: Achtung - Panzer! is a book by long-standing German General Heinz Guderian. First published in 1937, the book remains stalwart in the face of contemporary military strategy whereby the deployment of mechanized, armored divisions is central. The prospect of marrying army divisions with tanks, mortars, and other forms of mechanized artillery was a rather novel concept at the outset of World War II in Europe. Similar calls for mechanization were asserted by French commander Charles de Gaulle in the 1930s, but those calls were not heeded in France like they were in Germany. And it is fair to say that these innovative war tactics, embraced by the Germans, were a major reason why the Battle of France (Fall Gelb) lasted a mere two months in May and June 1940. As a result of Guderian's treatise on mechanized warfare, the German Army fashioned a series of Panzer Korps in order to bring his war theories to fruition. These Panzer Korps were outfitted with German Panzer and Tiger tanks which relied more on speed and nimbleness instead of armor and defense like the French FT-17.