This is a philosophical introduction to Aristotle, and Professor Lear starts where Aristotle himself starts. The first sentence of the Metaphysics states that all human beings by their nature desire to know. But what is it for us to be animated by this desire in this world? What is it for a creature to have a nature; what is our human nature; what must the world be like to be intelligible; and what must we be like to understand it systematically? Through a consideration of these questions Professor Lear introduces us to the essence of Aristotle's philosophy and guides us through the central Aristotelian texts - selected from the Physics, Metaphysics, Ethics, Politics and from the biological and logical works. The book is written in a direct, lucid style which engages the reader with the themes in an active, participatory manner.