Jazz..

Jazz is improvisational form of music that originated in the southern United States after the civil war. Although its origins and history are somewhat vague, we know that it began as musical expression of black people who had formerly been slaves, combining hymns, spirituals and traditional work of songs into something quite new. The style was a blend of the rhythms brought to America by the Africans who were imported as slave labor and the popular music of the era that featured the ragtime piano. The term jazz itself is of obscure and possible nonmusical origin, but it was first used to describe this particular kind of musical expression in about 1915.
A jazz band commonly includes four to twelve musicians with a relative large proportion of the group in the rhythm section. Customarily, there are a drummer, a bass player, and a pianist. Often there is also a banjo player or guitarist. In traditional jazz, the clarinet, trumpet and trombone carry the melody. In more modern jazz, the saxophone, violin and flute may also be included in the melody section.
Jazz first became popular outside the United States in the 1920s when jazz began to record, distribute, and even export their recordings to Europe. Since Jazz is improvisational, it does not exist in the form of printed scores , recorded performances were and still are the best way of preserving the music