"The people of Borthan are ruled by the Covenant. Established thousands of years ago by the original settlers, the Covenant teaches that the self is to be despised, and it forbids anyone to reveal his innermost thoughts or feelings to another. Driven from the country of Salla when his brother inherits the throne, Kinnall Darival has established a new life in another land where he has prospered. Although he has outwardly observed the Covenant all his life, inwardly he has committed a grave offense - for Kinnall is secretly in love with his bondsister, Halum."
006096 
Price: 7.95 USD

This vintage Ace Double contains the first book publications of Robert Silverberg's The Silent Invaders along with William F. Temple's Battle on Venus.
"Silent Invaders" - A science fiction adventure chronicling the clash of star spies, "Abner Harris came to Earth on a mission of extreme urgency. His orders said that the universe was in dander of enslavement by the pebble-skinned Medlins. And that the fight against their evil scheming called for him to assume the disguise of a flesh-and-blood Earthman. But once in that new synthetic body, he made a mind-numbing discovery: that the real villains of space were his own kind!."
"Battle on Venus" - "George Starkey had to find a way to stop the thousand year war on Venus before his little group of astronauts became early casualties. But where were the headquarters of the contending sides and how do you tell a robot tank that you're neutral. But George had an ally, a Venusian girl who thought stealing was virtuous-and, unknowingly, he had something else that turned out to be the most valuable substance on Venus-a box of chocolate bars!"
001744 
Price: 6.90 USD

"It is A.D. 2103. Tom O'Bedlam, like the wandering character in the medieval ballad, "Tom O'Bedlam's Song," feigns madness as a sane means of survival in a high-tech, post-industrial world. Only Tom knows that his 'Insanity' is his way of coping with the extraordinary powers he possesses - powers that enable him to send his mind out across unimaginable gulfs of space, touring other worlds and capturing them in his unconsciousness.
"When a star probe that has been journeying to Proxima Centauri - four light years from Earth - sends back images of life, it becomes clear that this is the same shimmering green world of Tom's imagination, the same images he has telepathically transmitted to others. Sometimes threatening, sometimes beyond belief, the distant worlds that communicate with Tom are ultimately revealed as not a threat but a salvation, and Tom O'Bedlam, 'poor Tom,' as he likes to refer to himself, has become their designated instrument and representative on Earth. "
007341 
Price: 10.00 USD