Mysteries of Unexplored Worlds #31

This anthology issue contains two science-fiction stories. "The Double Man" follows Captain Franz Kone of space exploration, who lands on a third planet of the Xerses Cluster and discovers it is barren and uninhabited, yet realizes he cannot be the only survivor of his expedition. In the second story, an alien visitor called "Giggling John" infiltrates Earth society by impersonating a human named Dave Coombs and schemes to transfer wealth from a wealthy guest to finance his alien civilization's needs, while the real Dave works to expose the imposter. The cover story "Terror Beach" depicts an underwater struggle for life and death involving a diver and a massive sea creature.