Gurdjieff (c. 1866–1949) wrote a diverse collection of piano pieces at his “Institute for the Harmonious Development of Man” at the Chateau du Prieuré d’ Avon at Fontainebleau near Paris in a unique collaboration with pupil Thomas de Hartmann, a Ukrainian composer. This music was composed most intensely between the years 1925 and 1927, after Gurdjieff’s near-fatal car accident of 1924 when all work on his “Movements” or “sacred dances” had ceased. Thus this music was not written for the Movements but for other spiritual purposes. Gurdjieff would whistle, sing, and tap Eastern-sounding melodies and rhythms, and de Hartmann was required to immediately transform these indications into written Western notation, adding suitable harmonies. Like Gurdjieff’s teaching overall, the piano music is best described as a blending of Eastern and Western elements. In Gurdjieff’s lifetime this music was not published or recorded, and was mostly performed within his circle of pupils, as is appropriate within an initiatory and personally transmitted spiritual teaching. This article explores the Gurdjieff—de Hartmann music and its relationship to Gurdjieff’s overall esoteric teachings. There will also be an examination of how Gurdjieff groups and musicians continue to keep alive this music today, and it will be shown that the large number of recordings released represent its greatest cultural penetration into wider society. Currently hundreds of these recordings are available though, interestingly, most “Work” members are critical of them, arguing that the music only has value when experienced live and in a Work context.