Thought can, & does, change the world. &, in turn, ideas evolve. Fundamentalism, globalisation & bioethics are defining our future just as Marxism, feminism or existentialism have influenced our present. So what do we need to know as we move into the 21st century? This is A. C. Grayling's personal & heartfelt guide to the ideas that shape our world. Covering religion, philosophy, scientific theory & political movements, each essay illuminates, elucidates & provokes. Written with Grayling's customary fire & erudition, the result is a book which arms readers with knowledge & engages them in philosophical debate.