“In the Mood” is a big band era #1 hit recorded by American bandleader Glenn Miller. Joe Garland and Andy Razaf arranged “In the Mood” in 1937-1939 using a previously existing main theme (see below) composed by Glenn Miller before the start of the 1930s. Miller’s “In the Mood” did not top the charts until 1940 and one year later was featured in the movie Sun Valley Serenade.