John Boyd was one of the most influential contemporary U.S. strategists. Although there have been a couple of biographies of him, this is the first full analysis of his thought and its intellectual and historical context. The author, like Boyd was, is an air force pilot (although Dutch) with a talent for theory. Boyd's corpus is remarkably slight and consists mainly of a collection of slides. His most famous idea -- the OODA (observation, orientation, decision, action) loop -- turns out to have been oversimple. His military history was often suspect. Yet, as Osinga shows, Boyd's ideas were the product of an extraordinary amount of reading that went well beyond the military sphere, picking up on the "scientific zeitgeist" of his time. Osinga provides lucid expositions of the various elements that Boyd synthesized into some truly original formulations and ways of thinking about strategy.