Like many of London's books, this was originally serialized in a periodical, in 1906-07.

In Before Adam Jack London obsesses over 'The stuff of our heredity' and of our ascent from 'the vanished Younger World.' The contention of his unnamed protagonist is that his unique nightmare-rich dream life is in fact rising racial memory from deep in prehistory. He claims that prehumen memories imbedded in our 'germ plasma' [DNA, I think] is the stuff of unexplained dreams, not reincarnation. At the time common dreams of falling or flight were ascribed to memories of past lives by many of the modernist cults, where the psychiatric field had its theory of dreams being metaphoric interpretations of waking events. In this curious tale London makes the argument that we carry deeply buried racial memory, and that an occasional 'hereditary freak,' such as the protagonist, might experience detailed recall.

What makes this story work—-and it must, for it is almost the entire novella—is that the narrative is almost exclusively the record of one chattering ape-man's life among the trees, open spaces, and caves of a primordial world. His name was Big-tooth and his best friend was Lop-ear. Jack London's unique talent for telling a story from the viewpoint of an animal, such as in White Fang and The Call of the Wild, serves him well here, as he makes the clearest case in all of fiction, for the theory of blood memory and intuitive eugenics that so informed the later works of Burroughs, Stoddard, Howard and Lovecraft and appeared central to Spengler's thesis of cyclic history.