Doubting Thomas presents a deep analysis of four key debates between Aquinas and his contemporaries, offering a fresh perspective on behalf of the saint's major critics. While Thomas Aquinas remains by far the most influential philosopher and theologian of the Middle Ages, many of his contemporaries considered him a dangerous innovator whose enthusiasm for the newly rediscovered Aristotle at points led him astray. Some theologians of the Franciscan Order, especially, were vocal critics of his thought. In Doubting Thomas, Brendan W. Case examines four interrelated critiques of Aquinas leveled by Franciscan theologians Bonaventure of Bagnoregio and his student Peter John Olivi over the nature of human knowledge, the proper way to understand how unity and trinity relate in God, the nature of time, and the nature of matter and its relation to spiritual beings. By arguing that the Franciscans had the better of Aquinas in each of these debates, Case offers a much-needed corrective to the one-sided focus on Aquinas's thought in recent theology and philosophy.