At a time when the U.S.-Mexican border was still not clearly defined and when the doctrine of Manifest Destiny and land hunger impelled the Anglo presence ever deeper and more intrusively into South Texas, Juan Nepomucino Cortina cut a violent swath across the region in a conflict that came to be known as The Cortina War. Did this border caudillo fight to defend the rights, honor, and legal claims of the Mexicans of South Texas, as he claimed? Or was his a quest for personal vengeance against the newcomers who had married into his family, threatened his mother's land holdings, and insulted his honor? Historian Jerry Thompson mines the archival record and considers it in light of recent revisionist history of the region. As a result, he produces not only a carefully nuanced work on Cortina--the most comprehensive to date for this pivotal borderlands figure--but also a balanced interpretation of the violence that racked South Texas from the 1840s through the 1860s. Cortina's influence in the region made him a force to be reckoned with during the American Civil War. He influenced Mexican politics from the 1840s to the 1870s and fought in the Mexican Army for more than forty-five years. His daring cross-border cattle raids, carried out for more than two decades, made his exploits the stuff of sensational journalism in the newspapers of New York, Boston, and other American cities. By the time of his imprisonment in 1877, Cortina and his followers had so roiled South Texas that Anglo reprisals were being taken against Mexicans and Tejanos throughout the region, ironically worsening the racism that had infuriated Cortina in the beginning. The effects of this troubled period continue to resonate in Anglo-Mexican and Anglo-Tejano relations, down to this very day. Students of regional and borderlands history will find this premier biography to be a rich source of new perspectives. Its transnational focus and balanced approach will reward scholarly and general readers alike.