He was a leading authority on G. I. Gurdjieff, becoming active in practical and thematic Gurdjieff studies from 1956, after studying with Kenneth Walker and later with Henriette H. Lannes ("Madame Lannes") as his Gurdjieffian teacher and mentor between October 1957 and December 1978.
In 1994, Moore published "Moveable Feasts: the Gurdjieff Work" in Religion Today, challenging certain significant innovations in Gurdjieffian theory and practice introduced worldwide by Jeanne de Salzmann, the Gurdjieff Foundation's de facto leader.
In "Gurdjieffian Confessions" (2005), Moore briefly sketched his personal life and provided candid and vivid glimpses of his 38 years as a member of The Gurdjieff Society in London, between 1956 and 1994.
Moore's 100-page biography was written in the style of Lytton Strachey's compact 1918 classic "Eminent Victorians".
Lord Pentland was president of the Gurdjieff Foundation of New York between its founding in 1953 and his death in 1984.