This work is for those who want to be better informed about the major turning points in the history of human thought. Arranged thematically, the book looks at key questions, such as: how and what can we know; does God exist; why do we exist; anything goes; and what are the boundaries of reality? A companion volume to A Brief History of Christian Spirituality and A Brief History of Christian Music, the book is a guide to over 40 of the world's major thinkers, including: Plato, Aristotle, Augustine, Descartes, Kant, Locke, Marx, Nietzsche and Freud. Ideas and movements covered include: feminism, humanism, rationalism, New Age and the paranormal. There are new chapters on Wittgenstein, postmodernism and fundamentalism. Arranged thematically, the book looks at key questions, such as how and what can we know? Does God exist? Why do we exist? What are the boundaries of reality?