New York: Ballantine Books, [1966]. Small octavo, pictorial wrappers. First edition. Ballantine U2285. Paperback original. "Five people start rebuilding civilization at the bottom of the ocean." - Gerber, Utopian Fantasy (1973), p. 161. [Reference: Anatomy of Wonder (2004) II-1241. Clarke, Tale of the Future (1978), p. 151. Reginald 15243].