This is one of the most recognizable and popular big band songs. Miller recorded it in 1939 and the song became wildly popular in early 1940, shortly before Billboard began publishing its "Music Popularity Chart." This makes it hard to gauge the song's appeal at the time, but it helped Miller become the top bandleader in the world - in that first Billboard chart he held down three of the Top 10 places.
"In The Mood" is an expression that indicates a desire to have sex. It's pretty innocent now, but was a little racy at the time.
This song was written by the Tin Pan Alley composers Joe Garland (music) and Andy Razaf (lyrics). Garland was the tenor sax player and arranger with Edgar Hayes and his Orchestra. The Hayes band recorded "In The Mood" for Decca Records in February 1938, 18 months before Miller recorded the tune. Later in 1938, Artie Shaw played the tune on the air in a 6-minute-plus, rather plodding arrangement. Glenn Miller reworked the arrangement, first played it in late July 1939 (a version is extant on CD), and recorded it for Bluebird on August 1, 1939 (Bluebird B-10416-A). The rest is history; he played it quite often on the air, featured it in his first film Sun Valley Serenade (1941), and continued to play it when he disbanded and joined the Army Air Corps (the 418th AAF Training Command Orchestra).
This was based on a song called "Tar Paper Stomp" which was recorded in 1930 by Joseph "Wingy" Manone, who was a bandleader from New Orleans. Manone later had his own remake called "Jumpy Nerves" on Bluebird (the label on which Miller's "In The Mood" was first issued).
In 1977, The Henhouse Five Plus Two (an alias of novelty singer Ray Stevens) had a top 40 hit in both the UK and US with his version of this song, which was basically Stevens imitating chickens clucking the tune.
Beatles producer George Martin had the orchestra play a little bit of this song at the end of "All You Need Is Love
Chet - Greenfield Center, NY