John Duns Scotus (1266-1308) was one of the most important theologians and philosophers of the Middle Ages with a considerable influence on both christian and secular thought. He was called the Doctor Subtilis for his penetrating and subtle manner of thought. Despite his importance and greatness, little is known about his life, and information on his life in older literature is often not correct. In this volume, Antonie Vos presents a new biography based on the facts and on the information given in the writings of Duns himself. Information in older literature is checked and often corrected, and new information is added.