Book excerpt: “In a government, military matters are the essential thing,” said Japan’s “Heavenly Warrior,” the Emperor Temmu, in 684. Heavenly Warriors traces in detail the evolutionary development of weaponry, horsemanship, military organization, and tactics from Japan’s early conflicts with Korea up to the full-blown system of the samurai. Enhanced by illustrations and maps, and with a new preface by the author, this book will be indispensable for students of military history and Japanese political history.