A good mythology needs a Genesis story. For Jasper Johns, the dawn of creation came in the late fall of 1954, and was instigated not by divine revelation but something close to it: a vision in a dream. A year out of the army, asleep in a loft in lower Manhattan, Johns closed his eyes and saw the Stars and Stripes in the dark, not fluttering, not flying over a battlefield, but on an easel—and he was there, too, painting it. It’s hard enough to remember a dream the next morning, let alone decades on, and Johns recounted his vision of himself painting a flag with slight variations in the decades that followed: he may or may not have told Robert Rauschenberg about it over breakfast. But the next day he was at work, and by the spring of 1955, he had completed the painting he had seen in his vision.

Flag now hangs in the Museum of Modern Art, and it is painting no. 5 in the enormous new catalogue raisonné of Jasper Johns, a five-volume monument to the most inscrutable figure in modern American art. The painting is five feet wide and three-and-a-half feet tall. A canvas of that size would have been too expensive for the young artist, so he took a bedsheet and stretched it across three wooden supports, one for the spangled canton, two for the stripes. He then applied layer after layer of enamel paint, but it took forever to dry, so he picked up a package of beeswax at a store around the corner from his Financial District loft. Melting the wax on his hot plate, stirring in oil paint and varnish, he produced a fast-drying encaustic that would yield a textured surface and would embalm collaged clippings from The New York Times and New York Daily News, a rag found on the street, and even a certificate of American citizenship. The stars, their points somewhat raggedy, cohered through the collaging of wax-dipped fragments, white or blue, along carefully penciled outlines.

Johns would go on to paint or draw more than three dozen flags. White Flag, painted in the summer of 1955 and now in the collection of the Metropolitan Museum of Art, is larger, ten feet by six and a half, and the flag pattern remains perceptible beneath its whited-out surface thanks to the collaged papers and a subtle use of charcoal. Gray Flag, from 1957, is even closer to a monochrome. There were double flags and triple flags, flags with forty-eight stars and flags with fifty, flags made from encaustic and oil paint and pastel and in one case Sculp-Metal, a medium for hobbyists that, as the ads went, “models like clay—hardens into metal!” One flag, drawn in ashy…