For many centuries, Aristotle's Physics was the essential starting point for anyone who wished to study the natural sciences This book begins with an analysis of change, which introduces us to Aristotle's central concepts of matter and form, before moving on to an account of explanation in the sciences and a defence of teleological explanation. Aristotle then turns to detailed, important, and often ingenious discussions of notions such as infinity, place, void, time, and conintuity. He ends with an argument designed to show that the changes we experience in the world demand as their cause a single unchanging cause of all change, namely God. This is the first complete translation of Physics into English since 1930. It presents Aristotle's thought accurately, while at the same time simplifying and expanding the often crabbed and elliptical style of the original, so that it is very much easier to read. A lucid introduction and extensive notes explain the general structure of each section of the book and shed light on particular problems.