Druidic lore and religion, the legends surrounding the lost continent Atlantis, and the myths of ""the edge of the world"", add more than the usual substance and a literary quality to this story of a dark Celtic cult and a twin world below seas. A trigger-tempered Irish hero, a mysterious girl suffering endless reincarnations, and a daredevil American submariner put an end to the activities of a black Archdruid. Excellent escape fiction which has a classical caste.