The condition of being unseen is a fantasy of power, and a metaphor for powerlessness. Illustration by Simon Prades

It is possible, according to many sources, to become invisible, but you must be patient, methodical, and willing to eat almost anything. One characteristic spell, recorded by the British polymath John Aubrey around 1680, instructs you to begin by acquiring the severed head of a man who has committed suicide. You then bury the head, together with seven black beans, on a Wednesday morning before sunrise, and water the ground for seven days with fine brandy. On the eighth day, the beans will sprout, whereupon you must persuade a little girl to pick and shell them. Pop one into your mouth, and you will turn invisible.

If you don’t have eight days to wait, you can, instead, gather water from a fountain exactly at midnight (invisibility spells are fetishistic about time management), bring it to a boil, and drop in a live black cat. Let it simmer for twenty-four hours, fish out whatever remains, throw the meat over your left shoulder, then take the bones and, while looking in a mirror, place them one by one between the teeth on the left side of your mouth. You’ll know you’ve turned invisible when you turn invisible.

I don’t recommend trying these spells. If you’re going to fail to disappear, you may as well do so through methods less gross and felonious: by reciting the names of demons in Latin, for instance, or carrying around a slip of paper with twelve numbers arranged in a mystical pattern, or trying on a lot of hats and cloaks and rings. Alternatively, you can endeavor to turn invisible through far more prosaic means and stand a decent chance of succeeding. Getting someone to distract your would-be observers works (ask a pickpocket), as does good camouflage (ask an octopus). Hunching your shoulders and staring at the ground isn’t foolproof, but it beats “The Joy of Cooking Cats.” Recent high-tech efforts to turn invisible are not, as yet, significantly more successful than magic beans, but they are more reputable, more lucrative, and, in the long run, more promising.

These strategies differ so dramatically that they raise an obvious question: just what is invisibility? Is it the condition of being transparent, so that all light passes through you undisturbed? Or of being cloaked in something all-concealing, like Harry Potter sneaking around Hogwarts? Or does it mean to be incorporeal, so that you exist but are made, like a thought, of nothing? Or does it simply mean to be overlooked? Is it always a property of whatever is unperceived, or can it be a limitation of the would-be perceiver? And why do we count as invisible the things that we do? Ghosts, gods, demons, superheroes, ether, X rays, amoebas, emotions, mathematical concepts, dark matter, Casper, Pete’s Dragon, the Cheshire Cat—what is all this stuff doing in the same category? And why have we ourselves expended so much imagination and energy in trying to join them?

These questions are not so much answered as provoked by “Invisible: The Dangerous Allure of the Unseen” (Chicago), by the British science writer Philip Ball. A former editor of Nature and the author of nineteen previous books (he should write about that superpower), Ball leads us on a very fun, largely chronological journey through invisibility, beginning with myth and early magicians, ending with quantum physics, and stopping along the way at Newton, Leibniz, microscopy, photography, spiritualism, B movies, and science fiction. He is lucid and interesting on every topic he touches, from the ghost in “Hamlet” to those unseen extra dimensions posited by string theory. But he is more a tour guide than a theorist, and he never entirely succeeds at pulling the category together, or illuminating our own ambivalent relationship to the prospect of becoming invisible.

Still, his book takes seriously a subject that, perhaps aptly, has heretofore been mostly disregarded. Invisibility looms large in the kingdom of childhood—in pretend play and imaginary friends, in fairy tales and comic books and other fictions for kids—but it seldom receives sustained adult scrutiny. And yet, once you get past the cloaks and the spells, invisibility is a consummately grownup matter. As a condition, a metaphor, a fantasy, and a technology, it helps us think about the composition of nature, the structure of society, and the deep weirdness of our human situation—about what it is like to be partly visible entities in a largely inscrutable universe. As such, the story of invisibility is not really about how to vanish at all. Curiously enough, it is a story about how we see ourselves.

If you are put off by magical methods for turning invisible, there are two other basic strategies available to you. The first is through technology; the second, through psychology. In a pattern you might recognize from the rest of life, the technological methods are exciting, expensive, and iffy, while the psychological methods are cheap, effective, and underappreciated.

In nature, the most successful invisibility technology, after being invisible, is camouflage. Perhaps you have seen a stick insect sitting on a stick, or a leaf-shaped katydid hanging from a branch—but probably you have not, so well do they blend in. Yet theirs is nature’s least and lowest kind of camouflage. When a flatfish hovers in the water, Ball tells us, sensors on its underbelly register the color and brightness of the surface below—information the fish uses to reproduce the look on its upper body, so that it matches its background. Some cephalopods see that trick and raise it, rather literally: they can change not only color but also texture, developing bumps or ridges (or, conversely, smoothing out) to mimic their surroundings. You can kill an entire workday watching videos of octopuses emerging from their hidden state; they look as if they have opened a door in space-time and are sliding back into the ocean from some other dimension.

Humans don’t come equipped with camouflage, but we can copy nature’s tricks. In our most basic efforts, we simply cover ourselves with material that matches our environment. Thus do duck hunters hunt ducks, and thus did Birnam wood come to Dunsinane. Post-Macduff, militaries got more sophisticated; by the early twentieth century, the British Navy was painting ships with bold alternating patterns of light and dark, which are not remotely invisible up close but, from a distance, break up familiar outlines and make shape recognition difficult. That technique is useful, but, as Ball points out, it illustrates a fundamental limitation of camouflage: it is, by definition, context-specific. You can blend in on a sunny day at noon or on a gray day at dusk, when seen from nearby or from afar, but you cannot do all of these at once—and you can’t repaint your battleship four times a day.

Or, anyway, you couldn’t. Recently, militaries have started exploring digital camouflage technology that would allow ships to function like flatfish, detecting their surroundings and changing in response. Using similar methods, the Japanese scientist Susumu Tachi is designing invisibility cloaks, and a suburb of Seoul is planning an invisible skyscraper. In theory, such technology mimics transparency, because you seem to be looking through the object to whatever lies behind it. The results, so far, are extremely cool, and extremely not invisible. You can spot the design flaw yourself, if you’ve ever watched the moon disappear behind the Flatiron Building as you cross Twenty-third Street: what’s behind an object depends, in part, on the location of the viewer. Even if digital camouflage could make a building seem to disappear from the perspective of one completely stationary observer (a big if), everyone else in the area would see it just fine.