The revolution of Charlie Parker’s music came down to two things: freedom and speed. Nobody had ever played so fast or with such intensity—nor had anyone strayed so far from the standard melodic course. There was a reason they called him Bird: He could make chaos sound not only natural but elegant, and no matter how much he looped or swooped, he always stuck his landing. To modern ears, the music Parker recorded for Savoy and Dial in the mid-to-late 1940s might sound old-fashioned. After all, his style—fluid, intricate, effortless—rhymes so closely with our public conception of jazz that its radicalism can go unnoticed, the way one might overlook a skyscraper or suspension bridge. At the time, the dominant style was big band, in which players were treated like pigments on a palette, applied at the careful discretion of the bandleader. Parker’s music, by comparison, was loose and informal, built on scraps of guidance that players were expected to build on, deviate from, or defy as suited their genius. In both cases, the individual mattered; the difference is that, with Parker’s approach, that individual wrote their own script—and wrote it in real time. Miles Davis (“Moose the Mooche”), Dizzy Gillespie (“Koko”)—if you want to know where they started out, it’s here. Not only did the sessions define bebop (a term Parker didn’t like), they captured the spirit of a world in which the machines were smarter, the weapons deadlier and the pace and feel of life were verging on abstraction. As the drummer Kenny Clarke later put it, Parker was running the same way everyone else was—he was just way out ahead.