This book offers a reconstruction, re-interpretation and re-evaluation of the philosophy of Epicurus. It aims to show that his thought represents the most significant and systematic philosophical contribution of the Hellenistic age; and speaks with special clarity and urgency to us who find ourselves in a similar predicament. The book opens with a sketch of the Hellenistic world and proceeds to consider in detail the principal ontological, epistemological and ethical tenets of Epicurus' philosophy.