Gnosis, the Greek word for knowledge, names, in the religious traditions that make it central, a direct, experiential and saving knowledge of the divine and of one's own true nature, sharply distinguished from ordinary intellectual or discursive knowledge. It is not information about God but an immediate inner realisation, held to transform and liberate the one who attains it. The idea stands at the heart of the ancient Gnostic movements of the early centuries of the common era, a diverse family of traditions that taught that the human being contains a divine spark, fallen or trapped in the material world, and that salvation comes through the awakening knowledge of one's divine origin and destiny, a knowledge that rescues the soul from ignorance and from the powers that hold it captive.
The theme is bound up with the ancient injunction "know thyself," and in the Hermetic tradition, the body of Greek philosophical and mystical writings attributed to Hermes Trismegistus, self-knowledge and knowledge of God are made one: to know oneself truly is to know the divine, for the self at its root is held to share in the divine nature. This conviction, that the deepest knowledge of the self is a knowledge of God, and that such knowledge is itself salvation, links the Gnostic and Hermetic currents to the broader mystical traditions, in which the realisation of the true self and the encounter with the divine converge. The pursuit of gnosis, as a transforming self-knowledge that saves, has continued to shape esoteric and mystical spirituality long after the ancient Gnostic sects themselves passed away, and it remains a central aim of much of the modern Western esoteric tradition.