Traversing the realms of science, politics, religion, culture, philosophy and history, Felipe Fernández-Armesto reveals the thrilling and disquieting tales of our imaginative leaps. Through groundbreaking insights in cognitive science, he explores how and why we have ideas in the first place, providing a tantalising glimpse into who we are and what we might yet accomplish. Fernández-Armesto shows that bad ideas are often more influential than good ones; that the oldest recoverable thoughts include some of the best; that ideas of Western origin often issued from exchanges with the wider world; and that the pace of innovative thinking is under threat.