Ideas can, and do, change the world. Just as Marxism, existentialism, and feminism shaped the last century, so fundamentalism, globalization, and bioethics are transforming our world now. In Ideas that Matter, renowned philosopher A.C. Grayling provides a personal dictionary of the ideas that will shape our world in the decades to come. With customary wit, fire, and erudition, Grayling ranges across the gamut of essential theories, movements, and philosophiesfrom animal rights to neurophilosophy to war crimesprovoking and elucidating throughout.Ideas are the cogs that drive history, and in explaining the most complex and influential ones in laymens terms, Ideas that Matter will help every engaged citizen better understand it.