New York: Fleming H. Revell Company, 1927. Octavo, pp. [1-6] 7-300 [301-306: blank] [notes: last three leaves are blanks; title leaf (included in the publisher's pagination as pages [3-4]) is part of an inserted conjugate pair, the other part being the frontispiece], inserted frontispiece (illustration uncredited) and title leaf, original blue cloth, printed paper labels affixed to front and spine panels. First edition. Classic 1920s science fiction awful warning story. Ancient advanced civilizations destroy themselves; two survivors mate with sub-humans to produce modern man. "Political thought in disguise. Competent and interesting. A timely book for international crises."- Bleiler, Science- Fiction: The Early Years 1692. [Reference: Clareson, Science Fiction in America, 1870s- 1930s 603. Locke, A Spectrum of Fantasy, p. 167. In 333. Bleiler (1978), p. 149. Reginald 10868].