Note: The 1957 Avon paperback (as Space Plague) is an abridgement of the 1956 Gnome Press first edition. The Lancer paperback reprint is unabridged.

Synopsis: From the back cover of the first Lancer printing: "Quest impossible - Someone had stolen an important part of Steve Cornell's life. It was bad enough when his fiancee vanished. It was infinitely worse when everyone in the world insisted it couldn't have happened the way he knew it had. In a world where ESP and telepathy were normal, it was difficult to keep secrets. But Steve's search for his missing sweetheart brought him to the threshold of one of the greatest secrets of all time. And it was obvious that somebody would stop at nothing to keep him from uncovering it. What were the oddly sinister symbols along the otherwise ordinary roads? What was behind the spreading plague called Mekstrom's Disease? Why were there "blank" spots where telepathy didn't work? Who was the elusive enemy with powers even beyond those ESP had bestowed on mankind? And, most important of all... could Steve find that enemy before they made him vanish too?"