Editio princeps of Peter Thomae's De enteIt is generally acknowledged by historians of philosophy that medieval philosophers made key contributions to the discussion of the problem of being and the fundamental issues of metaphysics. The Quaestiones de ente of Peter Thomae, composed at Barcelona ca. 1325, is the longest medieval work devoted to the problem of being as well as the most systematic. The work is divided into three parts: the concept of being, the attributes of being, and the descent of being. Many of the philosophical tools that Peter pioneered in this work, such as the distinction between objective being and subjective being, and various modes of quiddities and abstraction, were adopted by later thinkers and discussed up to the eighteenth century. Apart from defending and further extending Scotistic doctrine, one of Peter's achievements in the De ente is to fully reconcile Scotistic univocity with the traditional doctrine of the analogy of being.In addition to the critical edition, the present volume also contains a detailed introduction and study of the philosophy and the manuscripts of the De ente, with an appendix containing the question on univocity by Francis Marbres (John the Canon), who copied extensively from the De ente.