The spread of jazz.
 
In the 1940's and 1950's, the sophisticated forms of bebop and cool jazz began to gain wide acceptance among intellectuals and college students. Jazz concerts became popular. Groups of jazz stars made a series of international tours called Jazz at the Philharmonic. The international growth of jazz resulted in many successful overseas tours by U.S. bands and combos.
 
The introduction of the 331/3 rpm long-playing (LP) record, which was first produced commercially in 1948, also helped spread the popularity of jazz. For 30 years, jazz recordings had been limited to 78 rpm records that restricted performances to about 3 minutes in length. The LP allowed recorded performances to run many minutes. The LP also permitted a number of shorter performances to be issued on a single record.
 
During the 1950's, musicians in other countries began to improve greatly as jazz performers as they were exposed to performances by American musicians through recordings and concerts. Sweden, France, Germany, Japan, and other countries developed players and composers whose work compared favorably with that of the leading Americans. The first foreign jazz musicians to influence Americans were Belgian-born guitarist Django Reinhardt in the late 1930's, and George Shearing, a blind, English-born pianist who immigrated to the United States in 1947.
 
In 1954, the first large American jazz festival was held at Newport, Rhode Island. Since then, annual festivals also have been held in Monterey, California; New York City; Chicago; Nice, France; Montreux, Switzerland; Warsaw, Poland; Berlin, Germany; and many other locations throughout the world. These festivals have featured almost all of the most popular jazz musicians and have introduced many extended concert works.
 
New directions
 
Beginning in the 1950's, jazz became even more experimental. Jazz music began to feature nontraditional instruments, such as French horn and bass flute. Jazz musicians began to take an interest in non-Western music, especially the modes (different arrangements of scales), melodic forms, and instruments of Africa, India, and the Far East.
 
In the late 1950's, John Lewis, musical director of the Modern Jazz Quartet, worked with classical musician and composer Gunther Schuller to write and play orchestral works that combined elements of modern jazz and classical concert music. Stan Kenton also played this so-called third stream music when he toured the United States with a 40-piece orchestra.
 
Also during this period, pianist George Russell developed a jazz theory of modes. In 1959, the Miles Davis combo, with pianist Bill Evans and saxophonists John Coltrane and Cannonball Adderley, recorded compositions and improvised solos based on modes rather than on patterns of chords.
 
In 1960, saxophonist Ornette Coleman reshaped the thinking of younger jazz musicians when he recorded the album Free Jazz with a double quartet. In this recording, Coleman discarded harmony, melody, and regular rhythms. He substituted unstructured improvisation played atonally (in no definite key). Pianist Cecil Taylor and bassist Charles Mingus conducted similar atonal experiments.
 
In the 1960's, the influence of the music of India entered jazz through the adaptations of John Coltrane. Jazz musicians also began to use more unusual meters, such as 5/4, 7/4, and 9/8.