Herbert Eugene Bolton's The Padre on Horseback is a vivid portrait of Eusebio Francisco Kino, the intrepid Jesuit missionary who explored and evangelized the Pimería Alta region—modern-day southern Arizona and northern Sonora—during the late 17th and early 18th centuries. Kino's remarkable journeys on horseback took him across vast deserts and rugged mountains, where he established missions, mapped uncharted lands, and built lasting relationships with Indigenous peoples, particularly the Pima. Bolton captures Kino's dual role as a missionary and explorer, detailing his relentless efforts to introduce Christianity while advocating for Native rights against Spanish colonial exploitation. Through meticulous research and engaging storytelling, the book follows Kino's discoveries, including his definitive proof that Baja California was not an island but a peninsula. His dedication to both faith and science made him a pivotal figure in the history of the American Southwest. Rich with historical insight and adventure, The Padre on Horseback brings to life the legacy of a man whose influence extended beyond religion to geography, diplomacy, and frontier life. This classic biography is essential reading for those interested in Southwestern history, early exploration, and the cultural intersections that shaped the region.