A new jazz style called swing developed in the 1920s and flourished from 1935 to 1945, a decade nicknamed the ‘swing era’. Swing was played mainly by big bands, whose powerful sound could fill the large dance halls and ballrooms that mushroomed across the country, particularly after the repeal of prohibition in 1933. There were hundreds of ‘name bands’ – like those of Duke Ellington, Count Basie, Glenn Miller and Benny Goodman. Some bands featured singers like Billie Holiday, Ella Fitzgerald and Frank Sinatra. During the 1930s and 1940s, big bands were as popular as rock groups have been since the 1950s.

The typical swing band had about 14 or 15 musicians grouped into three sections: saxophones, brass instruments and rhythm instruments. A band of this size needed music that was more composed than improvised and was also arranged, or notated in written-out parts for each musician to read. With swing, the arranger became an important figure in jazz.

In a swing band, melodies were often performed by entire sections, either in unison or in harmony. Solos were restricted in length and frequently accompanied by saxophones playing sustained chords, or by short repeating phrases called riffs.

Not only was the swing band larger and more dependent on arrangements that before, it also had other distinctive features: the saxophone became one of the most important instruments of the era; percussionists had a more prominent role, often taking spectacular solos; and the beat was maintained in a new way. While the pulse continued to be maintained by the bass drum, percussionists now used the hi-hat to stress the 2nd and 4th beats of the bar: