Carl von Clausewitz was an outstanding young cadet in the Prussian army who never reached the high rank that he thought he deserved. In 1818, he was named director of the Prussian War College, an appointment he had not sought but that nonetheless gave him the time to work on his masterpiece, On War. Clausewitz died of cholera in 1831, having instructed his wife to organize the text and prepare it for publication. The book ultimately became a classic, and many experts in military affairs consider it the best book ever written on the subject. Stoker’s biography focuses mostly on Clausewitz’s military record, devoting just one chapter to the last 16 years of the Prussian’s life, during which time he wrote On War. This is a well-written and valuable addition to the Clausewitz library, but it also serves as a useful history of the Napoleonic Wars, as Stoker draws on Clausewitz’s sharp observations to illuminate some of the most important military engagements of that period.