The Pentagon is agog with discussions of a revolution in military affairs, the technologically driven transformation of warfare that some believe is now under way. This volume deals with a much earlier period, the mid-sixteenth through the mid-seventeenth centuries, from whence the term "military revolution" originates. The author, a historian at Yale, has assembled the best military historians of the period, including Michael Roberts, the most senior of them and the coiner of "military revolution." The themes here, particularly the impact of social change on the conduct of war, repay consideration by contemporary students of strategy. Reflection upon changes in warfare during this period may also prompt reflection on various metrics of change, including some (such as the transformation of concepts of discipline and hierarchy) that have resonance today. These military historians, many writing at the top of their form, have another lesson to teach contemporary strategic analysts: the merits of cross-national comparisons of military affairs.