"In The Mood" is an instrumental jazz and swing piece composed by Joe Garland in 1938. It gained immense popularity when it was recorded by the Glenn Miller Orchestra in 1939, becoming one of the defining songs of the swing era. The piece is characterized by its catchy melody, upbeat tempo, and distinctive use of brass and woodwind instruments. The song features a memorable riff that has made it a favorite for dance performances and big band concerts. Its infectious rhythm and lively arrangement have led to numerous covers and adaptations across various genres, solidifying its status as a classic in American music history.