As a composer, Dizzy Gillespie wrote dozens of original pieces that became foundational works of modern jazz. His compositions from the 1940s helped define the bebop vocabulary, introducing harmonic complexity, rhythmic intricacy, and structural innovation that broke sharply from the swing era. A Night in Tunisia, perhaps his most celebrated piece, features an unusual bass line and dramatic stop-time breaks that made it one of the most performed jazz compositions of the twentieth century. Salt Peanuts, with its playful vocal hook and blazing tempo, became an anthem of the bebop movement, while Woody 'n' You and Bebop further established the new harmonic language. Equally significant was Gillespie's pioneering role in Afro-Cuban jazz, composing Manteca and Tin Tin Deo with Cuban percussionist Chano Pozo. These pieces merged jazz harmony with Afro-Caribbean rhythmic patterns in ways that opened an entirely new direction for the music. Gillespie worked closely with arrangers Gil Fuller, Tadd Dameron, and George Russell to realize his big band compositions, which demanded both ensemble precision and solo virtuosity. His writing is characterized by angular melodies built on extended chord tones, unexpected rhythmic accents, and a sense of playful wit. These compositions remain central to the jazz repertoire and continue to challenge and inspire musicians.