Much more than your basic Roy G. Biv primer, this concise treatise on colors is as straightforward and as intoxicating as colors themselves. At the most basic physiological level, seeing a color is simply “the particular visual experience triggered by the detection of electromagnetic waves between about 390 and 700 nanometers.” At every other level, colors are more complex. There’s even something slightly miraculous about them; Newton saw just five colors in the rainbow, but because the world was created in seven days, he thought there should be seven, as in fact there are. Is believing seeing, or is seeing believing? “What we see are the colors of the mind,” Kastan says, since color vision is a mysterious interaction among the eye, the brain, light, objects, and any number of cultural associations. These various emotional, political, racial, and literary meanings are often contradictory and are constantly shifting. Many seem universal, like the equation of melancholy with blue (though blue is also part of the sky and water, so it’s no less true to call it transcendent and buoyant). Others are illusory: no actual flesh corresponds to white, black, or yellow, as Kastan’s discussion of Byron Kim’s “Synecdoche” brilliantly shows. For each of the ten colors Kastan discusses—the rainbow shades plus gray and the achromatic black and white—he has dozens of fascinating observations, from the etymology of the colors’ names to their artistic champions to their individual personalities. Violet is “purple lit from within,” for instance, and Indigo has a dark history. Orange took a long time to distinguish itself as a color, separate from the fruit. Which begs the question: do colors have an independent existence, apart from the objects that reflect them? And if so, where would that be? “Color happens rather than exists,” Kastan suggests. Think about that the next time you watch a sunset bursting into a color chart of reds.