Birth of the Cool is a compilation album by American jazz trumpeter and bandleader Miles Davis, released in February 1957 by Capitol Records. It compiles eleven tracks recorded by Davis's nonet for the label over the course of three sessions during 1949 and 1950. Featuring unusual instrumentation and several notable musicians, the music consisted of innovative arrangements influenced by classical music techniques such as polyphony, and marked a major development in post-bebop jazz. As the title suggests, these recordings are considered seminal in the history of cool jazz. Most of them were originally released in the 10-inch 78-rpm format and are all approximately three minutes long. Background From 1944 to 1948, Miles Davis played in Charlie Parker's quintet. Davis recorded several albums worth of material with Parker during this period, including Parker's Sessions for the Savoy and Dial labels. Davis' first records released under his own name were recorded with Parker's band, in 1947, and were more arranged and rehearsed than Parker's usual approach to recording. By 1948, Davis had three years of bebop playing under his belt, but he struggled to match the speed and ranges of the likes of Gillespie and Parker, choosing instead to play in the mid range of his instrument. In 1948, Davis, becoming increasingly concerned about growing tensions within the Parker quintet, left the group and began looking for a new band to work with. At the same time, arranger Gil Evans began hosting gatherings of like-minded, forward-looking musicians at his small basement apartment, located on 55th Street in Manhattan, three blocks away from the jazz nightclubs of 52nd Street. Evans had gained a reputation in the jazz world for his orchestration of bebop tunes for the Claude Thornhill orchestra in the mid-1940s. Keeping an open door policy, Evans' apartment came to host many of the young jazz artists of late-1940s New York. The participants engaged in discussions about the future of jazz, including a proposed group with a new sound. According to jazz historian Ted Gioia: [The participants] were developing a range of tools that would change the sound of contemporary music. In their work together, they relied on a rich palette of harmonies, many of them drawn from European impressionist composers. They explored new instrumental textures, preferring to blend the voices of the horns like a choir rather than pit them against each other as the big bands had traditionally done with