"Oliloqui Valley" is an original composition by pianist Herbie Hancock, written for his landmark 1964 album Empyrean Isles on Blue Note Records. The piece was recorded on June 17, 1964 at Rudy Van Gelder's studio in Englewood Cliffs, New Jersey, with Freddie Hubbard on cornet, Ron Carter on bass, and Tony Williams on drums. The composition follows a 28-bar ABAB' form, an asymmetrical structure that gives it a distinctive sense of forward motion and avoids the predictability of standard 32-bar forms. The title refers to ololiuqui, a hallucinogenic morning glory seed used in Aztec rituals, fitting the album's overarching theme of mythical, otherworldly landscapes suggested by the Empyrean Isles concept. Musically, the piece has a lyrical, impressionistic quality that sets it apart from the harder-driving tracks on the album. The melody unfolds over rich modal harmonies, with Hancock's voicings creating a spacious, contemplative atmosphere. The rhythm section plays with a relaxed but alert swing feel, and the modified final A section adds harmonic and melodic variation that deepens the compositional statement. Alongside "One Finger Snap," "Cantaloupe Island," and "The Egg," the tune helped establish Empyrean Isles as one of the defining post-bop albums of the 1960s and confirmed Hancock's stature as both a formidable pianist and an inventive composer at just twenty-four years of age.