Boris Mouravieff was an enigmatic `third man`, known to Gurdjieff and Ouspensky, who found and learned to practise what he clearly believed to be the complete system of which only `fragments` had been previously published in Ouspensky`s In Search of the Miraculous. On this basis, he formed the `Centre d`Etudes chretiennes esoteriques` in Geneva -- now closed. Many of his discoveries are described in his book Gnosis, which contains in its three volumes the fundamental components of that Christian esoteric teaching revealed by Ouspensky in fragmentary form. This Gnosis is not a modern statement of the second century texts known as `Gnosticism`, but a previously unpublished ancient Christian knowledge tradition. Boris Mouravieff taught Eastern Esotericism at Geneva University for many years, and Gnosis is the result of his teaching. First published in French in 1961, the three volumes of Mouravieff`s Gnosis have since been translated into Greek, and an Arabic text is in preparation. Now -- after seven years of work -- the translation of the first volume into English is available, Volume II is already translated and will be published in two years, and work has finally begun on Volume III. Translated from the French by S. A. Wissa. English text edited and revised by Robin Amis.