Gary's Notebook is an instrumental hard bop tune composed by Lee Morgan, the American trumpeter who lived from 1938 to 1972. Morgan is credited as its writer, and the known recording of the piece is also by him, made on 21 December 1963. The tune appears as track B1 on The Sidewinder, a Blue Note album released in 1964, where it runs 6:03.
The tune is listed under the jazz genre and the hard bop style, and as an instrumental it has no lyrics. The recording on The Sidewinder is the only one associated with the tune in the available material, so its character can be judged from that performance alone.