Last and First Men is a "future history" science fiction novel, describing the history of humanity from the present onwards across two billion years and eighteen distinct human species, of which our own is the first. Conception of history follows a repetitive cycle with many varied civilizations rising from and descending back into savagery over millions of years, as the later civilizations rise to far greater heights than the first. It is an early example of the fictional supermind; a consciousness composed of many telepathically linked individuals.