Just as bebop was a response to the limits of the swing era, cool jazz was a response to the complexities of bebop jazz. In the "cool era" jazz musicians moved jazz closer to classical music. Much more emphasis was placed on arrangement and composition rather than complex improvised solos. The term "cool" was actually invented by record companies and journalists. Musicians of this era disliked any labelling of their music and especially this one as they thought that it made out that their style of music was boring.

One of the defining elements of cool jazz was the different tone qualities that musicians aimed for. The tonal qualities of cool jazz can be described as calm, subdued, soft, or light. One of the most obvious tonal differences in this era from the eras preceeding it was the use of a much more delicate attack. Cool players also played with little or no vibrato. Unlike bop musicians who utilized the whole range of the instrument and often focused on the extremes fo the instrument, cool jazz musicians tended to use the middle registers.

Cool jazz ensembles were usually composed of three to eight players. These ensembles often utilized instruments that had not previously been used in jazz ensembles. These instruments included the flute, the French horn, the oboe, and the cello. Another important instrument that worked its way into jazz was the flugelhorn. The flugelhorn was used quite often by Miles Davis, one of the leaders of the swing movement. In addition to introducing new instruments to jazz, the cool era also introduced new formats for compositions and new meter signatures. Musicians no longer only played in 4/4 or 2/4 time. Meters such as 3/4, 5/4, and 9/4 became more common. Some musicians even adopted some classical forms such as rondos and fugues. These musicians moved even closer to traditional classical music and their type of jazz has been categorized as "third-stream music."

Some important artists of the cool era, and beyond, include Miles Davis, Stan Getz, Dave Brubeck and Charles Mingus.

This summary written by Sean Glass