Kenneth Bulmer - Of Earth Foretold (2nd Digit edition)

Originally published in the U.S. as "The Earth Gods are Coming" as part of an Ace Double with Margaret St. Clair's "The Games of Neith" in 1960. This second U.K. edition from Digit Books (R681) is undated but is circa 1963, and includes an extra novelette "The Aztec Plan". Cover art is not credited.