Gary's Notebook was composed by Lee Morgan and recorded on December 21, 1963, at Rudy Van Gelder Studio for Blue Note Records as part of the album The Sidewinder. The quintet featured Morgan on trumpet with Joe Henderson on tenor saxophone, Barry Harris on piano, Bob Cranshaw on bass, and Billy Higgins on drums. The composition is a dark, harmonically sophisticated 12-bar blues cast as a fast waltz in a minor mode, with a 16-bar introduction leading into 24-bar choruses. It opens with a tight, syncopated unison motif between trumpet and tenor, and its rhythmic character features tricky two-against-three effects between the bass drum and bass that launch the improvisational sections. The tune is named after a close friend of Morgan's, possibly Gary McQuade from his Philadelphia days. While the album's title track became an unexpected commercial hit, Gary's Notebook represents its deeper artistic ambitions, and critics have recognized it as one of the finest compositions on the record. One reviewer called it the best track on the album, noting that it sits somewhat in the shadow of The Sidewinder. The composition has remained a deep cut in the Morgan canon rather than entering the widely performed jazz standard repertoire, but it showcases Morgan's growth as a composer and his ability to balance accessibility with structural complexity. The original Blue Note session is featured on AllSolos with transcribed solos from Henderson, Morgan, and Harris.