Éliphas Lévi Zahed
According to Readers Guide to The Mahatma Letters to A. P. Sinnett:
Lévi, Eliphas, 1810-75. A pseudonym for Abbe Louis Constant, a French abbe, who became interested in occultism and the Kabbala and wrote extensively on such subjects. M and KH frequently referred to his writings and indicated that there was much of value in them if one had the right key to understanding. he was at one time a member of Bulwer-Lytton's club for the study of practical magic. ML index; LBS, Appendix 1; The Theosophist, January 1886; HPB IV: 136, 238, 439. 
- George E. Linton and Virginia Hanson, eds., Readers Guide to The Mahatma Letters to A. P. Sinnett (Adyar, Chennai, India: Theosophical Publishing House, 1972), 237-238.