This book examines the selected writings of John of Wales, a thirteenth-century Franciscan scholar. Though overshadowed historically by men like Thomas Aquinas and Bonaventure, John contributed significantly to the preaching explosion of the later Middle Ages, devoting his scholastic energies to the production of encyclopedic preaching aids for the growing number of the devout and learned emerging from the new universities. Through a detailed analysis of his world view, the author establishes John's strong interest in politics and contemporary social issues and helps to explain why his writings appealed to young preachers and the popular imagination. John's historic popularity and literary influence are also fully explored. His works seem to have been an important source of classical material for European literary texts of the period, and therefore, in addition to historians and theologians, this unprecedented book will appeal to those interested in the survival and transmission of Greek and Latin literature.