Jazz is a musical form that grew out of a cross-fertilization of folk blues, ragtime, and European music, particularly band music. It has been called the first native art form to develop in the United States of America. The music has gone through a series of developments since its inception. In roughly chronological order they are Dixieland, swing/big band, bebop, hard bop, cool jazz, free jazz, jazz fusion and smooth jazz.
Jazz is primarily an instrumental form of music. The instrument most closely associated with jazz may be the saxophone, followed closely by the trumpet. The trombone, piano, double bass, guitar and drums are also primary jazz instruments. The clarinet and banjo were often used, especially in the earlier styles of jazz. Although there have been many renowned jazz vocalists, and many of the most well-known jazz tunes have lyrics, the majority of well-known and influential jazz musicians and composers have been instrumentalists. During the time of its widest popularity, roughly 1920 to 1950, jazz and popular music had a very intimate connection. Popular songs drew upon jazz influences, and many jazz hits were reworkings of popular songs, or lyrics were written for jazz tunes in an attempt to create popular hits.
The single most distinguishing characteristic of jazz is improvisation. Jazz also tends to utilize complex chord structures and an advanced sense of harmony. These characteristics in combination with the use of improvisation require a high degree of technical skill and musical knowledge from the performers.
The art form today is a widely varied one, using influences from all of the past styles, although the root of modern jazz is primarily bebop. Modern jazz can also incorporate elements of rock and roll, electronica, and hip-hop.
Jazz was a direct influence on Rhythm and blues, and therefore a secondary influence on most later genres of popular music. Modern American art music composers have often used elements of jazz in their compositions.