We are not, at this moment in human history, experiencing a golden age of rationalism. Astrologers outnumber astronomers a hundred to one. It is illegal to teach the fundamental biological fact of evolution in many high-school biology classes. As many as one in six Americans believe they have been abducted by aliens, while fewer than one in sixty knows enough about the various sciences to argue intelligently against this common delusion. In short, we live in a scientifically advanced and technically dependent civilization in which only very few individuals understand science and technology. This is a recipe for disaster, but Carl Sagan has noticed. Many people had noticed the sky, too, but they did not write Cosmos. Sagan did. The Demon-Haunted World is the Cosmos of ignorance, superstition and psueudoscience, explaining the altogether understandable and human reasons for belief in the irrational or impossible. Each of its 25 chapters is a lesson in a particular brand of misbegotten beliefs, as well as meticulous instruction in the dying art of skepticism. The anecdotal style Sagan loves is used here to teach the reader everything from possible interpretations of alien abductions, to the design of "cold read" horoscopes that fit anyone, to—mischief lovers take note—histories of and instructions for the manufacture of UFO hoaxes, right down to crop circles. But, most significantly, The Demon-Haunted World is about how to think critically and judge the mechanics of an uncertain universe. Sagan loves the human sense of wonder, and he wants the human race to believe in something; it would just be preferable to him for that something to be rooted in our future and not in centuries of selfish, superstitious ignorance. That is the crowning glory of this document, and the quality that elevates it to the status of Truly Important Book: its message that skepticism and cynicism need not and should not be the same thing.