With a career spanning multiple decades—from the Civil War and Reconstruction to the Gilded Age and Progressive Era—John M. Schofield (1831–1906) left a lasting impact on the American military. Despite his accomplishments as a general and statesman, Schofield is arguably one of the most overlooked figures in the history of nineteenth-century United States. This rich biography, masterfully written by historian Robert Wooster, draws on fresh scholarship to place Schofield's remarkable career of military service within the broader contexts of American politics and social reform. Despite narrowly escaping expulsion before graduating from the U.S. Military Academy, Schofield advanced at a young age to the rank of general, holding several Union Army commands during the Civil War. Decades later he would be recognized with a Medal of Honor for his courage at the 1861 Battle of Wilson's Creek. His career of service had only just begun, though. In the wake of Reconstruction and in an era of limited government, Wooster explains, the nation needed its soldiers to serve as diplomats, administrators, and agents of empire. Schofield rose to these challenges, moving on to serve, among other roles, as envoy to France, U.S. secretary of war, and, in retirement, as advisor to presidents William McKinley and Theodore Roosevelt. Today he is familiar to many as the namesake for the Schofield Barracks on Oahu, Hawaii, established to defend Pearl Harbor. Through this unflinching biography, covering both Schofield's successes and shortcomings, Wooster delivers a broad narrative that moves beyond military experiences and unearths the complex relationship between the U.S. Army and American politics in the nineteenth century. At the same time, this volume reveals the inner workings and trajectory of the American military as it moved forward into the twentieth century.