Besides featuring all of VanVogts' worst tendencies in excess, it's a fixup fashioned from fundamentally disparate stories that are malled to fit together. The Changeling is better read by itself, and I'm hunting for the short story that features the million year old Neanderthal-"the Big Oaf" (that's what VanVogt says -a million years old). He is a somewhat amusing VanVogt creation, but even he can't save this carcrash of a novel.

Stay away. No good.