Ibrahim Ibn Sinan was one of the most famous scientists of the tenth century. His specialities were geometry, logic and philosophy of mathematics. In this volume, three new hypotheses are presented. The first one concerns the existence and the development of philosophy of mathematics in Arabic, independently of traditional metaphysics and philosophy. It is mainly concerned with the logic of discovery and the logic of proof. The second hypothesis concerns the development of a new chapter in mathematics devoted to geometrical transformations. The close connection between astronomy and mathematics, used to develop this last chapter, is discussed in the third hypothesis. The book presents a critical edition done for the first time and based on all available manuscripts, French translations, and long historical and mathematical commentaries.