Lloyd Ridgeon specialises in Sufism, particularly the medieval Persian Sufi tradition. His 1996 PhD on the thirteenth-century Persian Sufi, ʿAzīz Nasafī has been published in the Sufi Series, as have his monographs on Aḥmad Kasravī and on Javānmardī. He is the Editor of IRAN, and also the British Journal of Middle Eastern Studies.