The Mystical Science of the Soul explores the unexamined influence of medieval discourses of science and spirituality on recogimiento, the unique Spanish genre of recollection mysticism that served as the driving force behind the principal developments in Golden Age mysticism. Building on recent research in medieval optics, physiology, and memory in relation to the devotional practices of the late Middle Ages, Jessica A. Boon probes the implications of an 'embodied soul' for the intellectual history of Spanish mysticism. Boon proposes a fundamental rereading of the key recogimiento text Subida del Monte Sion (1535/1538), which melds the traditionally distinct spiritual techniques of moral self-examination, Passion meditation, and negative theology into one cognitively adept path towards mystical union. She is also the first English-language scholar to treat the author of this influential work - the Renaissance physician Bernardino de Laredo, a pivotal figure in the transition from medieval to early modern spirituality on the Iberian peninsula and a source for Teresa of Avila's mystical language.