Logic is often perceived as having little to do with the rest of philosophy, and even less to do with real life. In this engaging and accessible introduction, Graham Priest shows how wrong that conception is. He explores the philosophical roots of the subject, explaining how modern formal logic deals with issues ranging from the existence of God and the reality of time to paradoxes of probability and decision theory. Along the way, Priest lays out the basics of formal logic in simple, nontechnical terms.