Ace Double Novel: The Dark Intruder & Other Stories by Marion Zimmer Bradley

The Dark Intruder & Other Stories (1964), a collection by Marion Zimmer Bradley

At left: Paperback (New York: Ace Books, 1964), 124 p., #F-273, 40¢. Cover art and illustrations by Jack Gaughan. An Ace double novel, bound with Bradley’s Falcons of Narabedla.

Here’s the blurb from inside the front cover:

"Xanadu was a name to chill men's blood -- that is, all but Andrew Slayton's. For him discovering the lost city of Xanadu on the planet Mars was an exciting challenge. His ardor to find this solitary remnant of a Martian civilization long vanished was only the more increased by the knowledge that all those before him in the search had returned insane. But even his indomitable courage faltered when, one day while out searching alone, a disembodied voice suddenly announced quite clearly, “I am Kamellin.” The Dark Intruder, the unforgettable story of Slayton’s quest, is but one of
the seven exciting science-fiction adventures included in this new collection.”

The short story “The Dark Intruder” was originally published under the title “Measureless to Man” in the December 1962 issue of Amazing Stories magazine. An excerpt from the story is available
at Fictionwise. The collection The Dark Intruder & Other Stories was reviewed by SFF critic Rich Horton.

Also of interest: the website of the Marion Zimmer Bradley Literary Works Trust.