Students of Thomas Aquinas have so far lacked a comprehensive study of his doctrine of the transcendentals. This volume fills this lacuna, showing the fundamental character of the notions of being, one, true and good for his thought. The book inquires into the beginnings of the doctrine in the thirteenth century and explains the relation of the transcendental way of thought to Aquinas's conception of metaphysics. It analyzes "Being," "One," "True," "Good" and "Beautiful" individually and discusses their importance for the philosophical knowledge of God. "Medieval Philosophy and the Transcendentals: The Case of Thomas Aquinas" is intended as a contribution to the question "What is philosophy in the Middle Ages?." It argues that the doctrine of the transcendentals is essential for understanding medieval philosophy.