Cool jazz describes an alternative to the fiery virtuosity and blinding velocity of the bebop that emerged in the mid-'40s, yet there was nothing glib about music that fit under this large umbrella. The landmark 1953 Miles Davis album Birth of the Cool gave the aesthetic its name—with gorgeously opaque arrangements and a measured swing in response to bebop’s frenzied drive—but musicians were already experimenting with chill atmospheres and relaxed tempos, emphasizing liquid melodic flow as well as chamber-like settings. Horn players like Lee Konitz and Chet Baker adopted airy, silken tones that belied the harmonic sophistication of their lines, which often came in fleet multi-linear tangles. Big-band leaders like Gil Evans and Stan Kenton deployed rich arrangements that stressed gauzy timbres and counterpoint as much as swinging rhythms.