In The End of Catholic Mexico: Causes and Consequences of the Mexican Reforma (1855-1861), historian David A. Gilbert provides a new interpretation of one of the defining events of Mexican history: the Reforma. During this period, Mexico transformed from a Catholic confessional state to a modern secular nation, sparking a three-year civil war in the process. While past accounts of the Reforma have foregrounded its class dimensions and portrayed it as a liberal triumph over conservative elites, Gilbert instead argues that the Reforma was a religious war fueled two competing interpretations of the Catholic faith. These competing interpretations, Gilbert contends, generated sharp disagreements about Mexico's future, which further polarized the country and led to a culture war centered on religion. Gilbert's fresh account of this pivotal moment in Mexican history will be of interest to scholars of Latin American religious history, nineteenth-century church history, and US historians of the antebellum republic.