Aristotles metaphysics discusses what exists and how to understand it. It is because of Aristotle that metaphysics became known as metaphysics. Literally, it means after physics and was called that because Aristotle wrote the work after he wrote the Physics. It is in this book that Aristotle expands on the metaphysical work he has already done in the Categories. He explains his theory of substance, causation, the relationship of matter and form and ends with a proof of the existence of God. The current best translation of the metaphysics is found in The Complete Works of Aristotle, Vol 2.
Scholars today do not agree on how the book was written, which parts of it were written first and even whether or not Aristotle wrote all of this work himself. It is common to claim that the book was organized in its present form well after Aristotle was dead.
The Metaphysics was translated by many people throughout history. There were also many commentaries.