On the Padres' Trail begins with the arrival of Europeans in the New World and the invasion of the Caribbean, from which author Christopher Vecsey traces the expansion of Catholicism into New Spain. He devotes special attention to the history of the Catholic faith and institutions among the Pueblo peoples of New Mexico, particularly in the years since the establishment of the Archdiocese of Santa Fe. Then, he turns his attention to the history and effects, both good and bad, of the Catholic missions among the Indians of California. In the final section of the book, he details the history of the judgments made about Catholic missionizing in California (and, by extension, all of New Spain) closing with the sometimes critical perspectives of contemporary Native American Catholics regarding the padres who first brought Catholicism to their ancestors.