The story of Jim Pandrake ,who finds a strange engine ,with even stranger powers. That finding effects Jim's personal life ,changes the delicate ballance of super-powers in the world ,and confronts Jim with a group of immortals ,ruled by a 1,000,000 years old neanderthal.
A returning flaw in the works of A.E.Van Vogt ,is the fact that the book is packed with excellent sci-fi ideas ,but none is fully developed ,a fact that creates in the reader a lack of satisfaction ,even if the plot ended satisfactorily. And it did. Not one of his best ,but certainly not one of his worst , "Moonbeast" ,a.k.a "The Beast" ,gives you a solid typical Van-Vogt mind-thrill.