In 1930s and 1940s America, some jazz bands grew into much larger groups of musicians. These became known as 'swing bands' or 'big bands'. The instrumentation was:
Each band had its own arranger, who wrote the music. Although there were still some improvised solos in swing music, playing the parts that were written by the arranger was very important.
Famous bandleaders from this era include:
Swing music became popular around the world and the UK developed its own big bands. The audio clip below is of Lew Stone and his band, who were one of the most successful British big bands of the 1930s.