All About Rosie is based, according to the composer, "on a motif taken from an Alabama Negro children’s song-game entitled 'Rosie, Little Rosie'." The work is in three movements. In the first, fast-paced and set in alternating 2/2 and 3/2 meters, the composer builds through gradually mounting rhythmic and dynamic tension to a sudden climatic ending.
The second movement is slow and has a distinct blues feeling. At first, vaguely pan-tonal, i.e. avoiding a specific key, the music gradually coalesces into a definite tonality, chromatically enhanced. A climax is reached with the two trumpets intoning the theme over a rich, swinging accompaniment. There is a sudden relaxation, and on a short questioning note the movement ends much as it began.
In the third section the fast relentless pace of the opening is resumed, with the element of improvisation now added for the first time. Various improvised solos follow, including a virtually a capella stop-time chorus for piano. A recapitulation of the exposition of the first movement leads to a brilliant C major ending.