West Coast Cool

Music - low key undramatic rich orchestral sounds more akin to European impressionists than Ellington or Henderson. Moderate tempo and volume, tranquil, introspective and pensive. Growing out of Lester Young. Gone are the four square dancing rhythms. 3/4 and other time signatures emerge and section lengths become irregular .
Chronology - perhaps there were at least two reactions to Bop. One was the Dixieland Revival and the other West Coast 'cool'.
The fever of Bop produced an intellectual reaction in mainly thoughtful whites, not back to the roots in New Orleans but more to classical European orthodoxy. 
Stan Kenton's 'Artistry in Rhythm' was based on Ravel's Daphnis and Chloe. A trend to more complex arrangements begins.
Woody Herman and his Herds started with the blues and swing but introduced classical devices from Stravinsky.
Claude Thornhill and Gil Evans moved in the same direction.
The Europe influence peaked with 'The Birth of the Cool' and the written arrangements of Gerry Mulligan and Gil Evans.
After 'The Birth of the Cool' Gerry Mulligan moves to California and plays distinctive 'cool' jazz.
1952 'Gerry Mulligan Quartet' - Chet Baker at 'The Hague' LA.
Dave Brubeck moves on from the Wolfpack and studies before creating waves with new time and Paul Desmond.
1956 'The Steamer' Stan Getz - 
1960 'Django' The Modern Jazz Quartet - John Lewis and Milt Jackson, contrasting the frenetic hot sound of Parker, tried to keep jazz cool and in the dignified atmosphere of the Concert Hall 
West Coast - Shelly Mann, Shorty Rogers, Lee Konitz, ...