Henry Eustace McCulloch provides the first comprehensive account of a pivotal nineteenth-century military leader and politician from Texas. In his military career, Henry McCulloch served with his brother Ben in one of the first Texas Ranger companies after the Texas Revolution of 1836, defended settlers during the Great Comanche Raid of 1840, and helped to defeat Mexican forces that reoccupied San Antonio in 1842. He also served as a captain in the United States Army during the Mexican-American War. In the 1850s, voters in Texas elected McCulloch to the state legislature, where he advocated for creating additional Ranger units to defend settlers on the frontier. He was an enslaver who supported secession and commanded a regiment of Rangers that became the first unit sworn in by the Confederacy. McCullough later served as the temporary commander of the Department of Texas, directed regiments defending territory around San Antonio, briefly led the Texas Division, and participated in the attack at Milliken’s Bend, Louisiana. After the Civil War, McCulloch remained active in politics, leading a group supporting Richard Coke during the Coke-Davis imbroglio in 1873 and running as the Populist Party’s candidate for governor in 1892. David Paul Smith’s biography reveals McCulloch’s involvement in events that shaped nearly all of nineteenth-century Texas history, restoring his legacy as one of the state’s most important military leaders and politicians.