A big band is a type of musical group that plays jazz music. They were very popular in the 1930s and 1940s. A big band usually has between 12 and 25 musicians. They include a singer and people who play instruments like saxophones, trumpets, trombones, drums. Some famous big band leaders were Duke Ellington, Benny Goodman, Glenn Miller, Cab Calloway and Count Basie.