Thomas Alexandrovich de Hartmann (Russian: Фома́ Александро́вич Га́ртман) September 21, 1885 – March 28, 1956 was a Russian composer and prominent student and collaborator of George Gurdjieff. Thomas de Hartmann was born in Khoruzhivka, Poltava Governorate, Russian Empire, now Sumy Oblast, Ukraine. At the age of 18 he received his diploma from the Saint Petersburg Conservatory. He studied conducting in Munich with Felix Mottl before World War I. Thomas de Hartmann was a graduate of the Imperial Conservatory of Music. He studied musical composition with three of the greatest Russian composers of the 19th century: Nikolai Rimsky-Korsakov, Anton Arensky and Sergei Taneyev. His piano teacher was Anna Yesipova, the second wife and former student of Theodor Leschetizky. Most of de Hartmann's compositions were for voice and piano. In 1907, his ballet The Pink Flower, produced by Sergei Diaghilev with Vaslav Nijinsky and Tamara Karsavina in the cast, was presented at the Imperial Opera. The Tsar was so impressed that he himself granted de Hartmann exemption from military duty so that he might study conducting in Munich. In Munich, Thomas de Hartmann met the artist former Sufi student and later stage impresario Alexander de Salzmann; they were both friends of Rainer Maria Rilke and Wassily Kandinsky. Later, in Russia, after the beginning of World War I, de Hartmann would introduce de Salzmann to George Gurdjieff. Thomas married Olga Arkadievna de Schumacher, a celebrated opera singer; her father was a high official in tsarist Russia. Thomas was the nephew of Eduard von Hartmann, the author of Philosophy of the Unconscious, a book published in Germany in 1869 but well known in America and England. De Hartmann was already an acclaimed composer in Russia when he first met Gurdjieff in 1916 in St. Petersburg. From 1917 to 1929 he was a pupil and confidant of Gurdjieff. During that time, at Gurdjieff's Institute for the Harmonious Development of Man near Paris, de Hartmann transcribed and co-wrote much of the music that Gurdjieff collected and used for his movements exercises. De Hartmann wrote Our Life with Mr. Gurdjieff together with his wife Olga de Hartmann, who was Gurdjieff's personal secretary for many years. De Hartmann died on March 28, 1956, in New York City, New York, USA. After her husband's death, Olga collected many of Gurdjieff's early talks in the book Views from the Real World (1973). Olga died in Santa Fe, New Mexico in 1979. De Hartmann's four-act ballet La Fleurette Rouge was performed in 1906. Vaslav Nijinsky, Anna Pavlova, and Michel Fokine were principal roles in performances at the Imperial opera houses of Moscow and St. Petersburg. He composed the music for Wassily Kandinsky's The Yellow Sound. The music he wrote with Gurdjieff was later adapted by Laurence Rosenthal for the 1979 Peter Brook film Meetings with Remarkable Men. In 1982, the Guggenheim Foundation premiere of Kandinsky's opera Der gelbe Klang was made possible thanks to a complete rearrangement by Gunther Schuller of de Hartmann's hitherto lost work. It is not known whether de Hartmann completed a full score but it is clear why Constantin Stanislavski could not understand the work when de Hartmann proposed it for the Moscow Art Theater in 1914.