Gardner was born in London on 31 March 1857, the son of an accountant. His parents were spiritualists and psychic sessions were held at his house, and sometimes, the young Gardner "incorporated" an Indian guide.
Career
He began his career as a clerk for a stockbroker, eventually becoming, himself, in 1886, a broker at the Stock Exchange, where he retired in 1903, becoming an antiquarian bookseller.
He wrote Catalogue Raisonné of Works on the Occult Sciences, a private edition published in three volumes on the occult sciences, consisting of Rosicrucian, astrological and Masonic texts, which is still a source of reference for scholars of occultism.
References
Howe, Ellic. The Magicians of the Golden Dawn. London: Routledge & Kegan Paul, 1972.