Ace Double D-453 (1960): The Earth Gods are Coming, bound with The Games of Neith. This is the first paperback appearance for either novel.

The Earth Gods are Coming, by Kenneth Bulmer. Cover by Ed Valigursky; 107 pages. Magazine version in the British continuation of Science Fiction Adventures May 1960 as "Of Earth Foretold." To pave the way for galactic conquest, a united Earth had invented the robot Messiahs. These ingenious devices, dropped from space, created on each alien planet a new and convincing faith - based on the future coming of the men from Earth. Roy Inglis was a trouble-shooter for the "Earth Gods" operation and he was among the very few who knew that someday they would run into the synthetic equivalent of the Devil. There'd be another set of interplanetary missionaries - only these would be monsters from some anti-Earth part of the universe. But he never realized that he himself could be the first convert to the creed of the Evil Ones - and that he might never know it until it was too late for the rest of humanity!

(Bound with) The Games of Neith by Margaret St. Clair. Cover by Ed Emshwiller; 149 pages. The people of Gwethym were highly intelligent, rational beings. They worshippe the goddess Neith, not because they believed in such a golden-haired being, but because they recognized the need for religion as a counterbalance to human passions. So when trouble struck their planet, when they discovered an energy leak which was slowly destroying their world, the Gwethymian turned to science for their answer. If their world was to be saved, the solution must come from the logicians. Or so they thought, until one day a woman, the image of their goddess Neith, walked across the waters of the harbor and into their city! Then their trouble was two-fold: Would there be anything left to save of their world if they waited for the scientists? And if they didn't, if they put their trust in this goddess whom logic told them could not even exist, would they just be sealing their doom that much quicker?