This revolutionary study by the renowned classical philologist reveals the interplay of Greek and Indian thought at the roots of Western culture. Thomas C. McEvilley's magisterial work demonstrates that Eastern and Western civilizations have not always had separate, autonomous metaphysical schemes, but have mutually influenced each other over a long period of time. Examining ancient trade routes, imperialist movements, and migration currents, he shows how some of today's key philosophical ideas circulated freely in the triangle between Greece, India, and Persia, leading to an intense metaphysical interchange between Greek and Indian cultures. While scholars have sensed a philosophical kinship between Eastern and Western cultures for many decades, The Shape of Ancient Thought is the first study to provide the empirical evidence. Covering a period ranging from 600 B.C. until the era of Neoplatonism and a geographical expanse reaching across the ancient world, McEvilley explores the key philosophical paradigms of these cultures, such as Monism, Pluralism, and reincarnation, to reveal striking similarities between the two metaphysical systems. Based on 30 years of intense intellectual inquiry and research and on hundreds of early historical, philosophical, spiritual, and Buddhist texts, the study offers a scope and an interdisciplinary perspective that has no equal in the scholarly world.