Nicholas of Cusa (1401-1464) is perhaps the most important philosopher of the fifteenth century. A lawyer by profession, his interests went beyond all boundaries of specialties, so he cultivated mathematics and astronomy, developed instructions for a better investigation of nature, he designed a new cosmology and developed a new concept of man, based on an origin creative. Nicholas of Cusa wanted to achieve a reform of all knowledge and to that end is looking for a new global perspective of the whole tradition of philosophy esecialmente and Neo-Platonic. In this book, Kurt Flasch, one of the foremost authorities on medieval philosophy at the Cusano, introduces the reader to the ideas of this original thinker and discusses his experiments with unhurried thought. Its purpose is to make a careful description of not only isolated theorems, but also their logical linkages and historic place which is situated the source. The theme of this introduction is the work of BERYLL (the lens), in which Nicholas of Cusa explains its fundamental ideas in their mature form and focuses on the problem of the coincidence of opposites.