*Liber LI: The Lost Continent* is a short occult-fictional work by Aleister Crowley, written around 1913, presented as a pseudo-historical account of Atlantis narrated by one of its seven mystical heirs. Crowley himself describes it as a hybrid: part Utopian fantasy, part social satire on contemporary civilization, and part veiled exposition of magical doctrine. The text recounts the civilization of "Atlas" (Crowley's preferred name for Atlantis), detailing its eugenicist social engineering — artificially accelerated puberty, shortened gestation, and voluntary euthanasia of the unproductive — framed approvingly as rational optimization of human potential. It offers an extended pseudo-etymological system claiming that major words in Greek, Latin, and religious vocabulary (including "Christos," "Mithras," and "Abraxas") derive from an ancient Atlantean root language built on sexual-solar symbolism. The work traces Atlantean history through conquest, magical development, and the discovery of "Zro" — a mysterious substance whose successive refinements eliminate disease and death — culminating in a political crisis when a faction argues further progress is unnecessary. Distinctive for its unapologetic blending of occult cosmology, eugenic ideology, and satirical political commentary, the text reads as Crowley using myth-making as a vehicle for his actual esoteric and social views rather than as straightforward fiction.