Trent Hone argues that the Navy created a sophisticated learning system in the early years of the twentieth century that led to repeated innovations in the development of surface warfare tactics and doctrine. The conditions that allowed these innovations to emerge are analyzed through a consideration of the Navy as a complex adaptive system. Learning War is the first major work to apply this complex learning approach to military history. This approach permits a richer understanding of the mechanisms that enable human organizations to evolve, innovate, and learn, and it offers new insights into the history of the United States Navy.