If you could be invisible, what would you do? The chances are that it would have something to do with power, wealth or sex. Perhaps all three, given the opportunity. But there's no need to feel guilty. Because these impulses, and plenty more, have always been at the heart of our fascination with invisibility. Precisely because it points to realms beyond our senses, the notion of invisibility has long performed as a receptacle for fears and dreams, as something that hints at worlds where other rules apply; and as a mighty power and a terrible curse, a sexual promise, a spiritual condition. This is a history of invisibility in our culture. It takes in Plato, the occult in the Renaissance and the Middle Ages, Shakespearian ghosts, ether and cathode rays and nineteenth-century science, spiritualism, electromagnetism, H.G. Wells, the microscopic world, camouflage, prestidigitation and twenty-first century nanoscience. Here is everything you've ever wanted to know about the invisible - from the medieval to the cutting-edge, fairy tales to telecommunications, from beliefs about the supernatural to the discovery of dark energy.