Gnosticism is less a single religion than a diagnosis: the world as given is broken, the true divine is far beyond the maker of this world, and liberation comes through direct gnosis — knowledge as recognition, not belief.
Its great themes — the fall of sophia, the creation by a demiurge, the awakening of the divine spark in each person — appear in the Nag Hammadi library, including the Gospel of Thomas.
Declared heretical by the early church, Gnostic currents resurfaced in Manichaeism, Catharism, Renaissance hermeticism, and modern psychological readings (Jung).