This book provides key reading for a correct interpretation of Aristotle's Metaphysics, posing problems to be resolved before any reader approaching the subject. Professor of History of Ancient Philosophy Giovanni Reale an analysis of the meaning of which is the title and provides a comprehensive and thorough study of the genesis and structure of the work itself. From the literary point of view, metaphysics is not a work unit, but a set of books and, more precisely, notes and materials of various kinds related to the lessons taught by Aristotle on a particular issue that he designated with various names and in particular, the technical expression "first philosophy". If the literary unity of the Metaphysics is now definitively excluded, a point which modern and contemporary studies leave no doubt, can not be said of the unit content of the collection are the fourteen books, which also can and should be read in the order in which we have been transmitted. Only with full awareness of such problems can benefit from reading the complex and abundant material presented in the books of the work. The author describes the structure of metaphysics through a systematic analysis of each book, going on a first chapters, and highlights and interprets the theoretical framework of metaphysical thought Aristótelesmostrando its foundations, key concepts and internal interlocking. After examining the similarities and differences between the structural and metaphysical thought of Plato, the book concludes with a history of the fortune of Metaphysics through the various interpretations that have been over the centuries, from the antiquity, Middle Ages, the Renaissance and the "second Scholasticism" to the modern age and the twentieth century.