A British army major whose father participated in the 1920s debates over military mechanization, the author views blitzkrieg as more than the application of modern technologies to warfare: blitzkrieg replaces the Clausewitzian theory of destroying enemy forces with the principle of destroying their will to fight. Messenger detects the rudiments of blitzkrieg in WW I battles like Cambrai, where British tanks smashed the Hindenburg line, and the German capture of Riga using air bombardment in 1917. The book describes the proselytizing efforts of early theorists of air war like Trenchard, Mitchell, and Douhet and exponents of mechanization like de Gaulle, Tukachevsky, von Seekt, and Liddell Hart. Yet, except for an appreciation of Tukachevsky's strategic brilliance, Messenger sidesteps the global parameters of blitzkrieg, including its diplomatic and logistical aspects, grasped by de Gaulle in particular. Instead the obvious is stressed: exploiting breakthroughs, by-passing enemy strongpoints, coordinating tank formations and mobile infantry--one of which, as a matter of fact, was alien to Clausewitz. The book tends to bog down in anecdotes about battles in the Spanish Civil War, the Mideast, and of course WW II, where Hitler is largely blamed for the Reichswehr's failures and again logistics go unexamined. This is intended as an exposition of the theory and practice of blitzkrieg, but the want of theoretical follow-through makes the pratical illustrations pedestrian, even for general readers.