The idea of Texas was forged in the crucible of frontier warfare between 1822 and 1865, when Anglo-Americans adapted to mounted combat north of the Rio Grande. This cavalry-centric arena, which had long been the domain of Plains Indians and the Spanish Empire, compelled an adaptive martial tradition that shaped early Lone Star society. Beginning with initial tactical innovation in Spanish Tejas and culminating with massive mobilization for the Civil War, Texas society developed a distinctive way of war defined by armed horsemanship, volunteer militancy, and short-term mobilization as...