Cradle of the Sun

This is a pulp science-fiction novel that was apparently written in about two weeks, but there's an unusually good McGuffin. It's one of those books where a Mad Scientist comes up with an invention that's going to destroy the human race. Usually, the invention is something prosaic, like a virus or a breed of killer robots or a transdimensional wormhole to a planet of evil demons, but Stableford had a better idea.