Slater’s Planet was published in 1971 by Pinnacle Books, publishers of the Mack Bolan: The Executioner series as well as Stay Young With Astrology, both advertised on the book’s last page. A quick look online reveals almost zero information about Harris Moore.[UPDATE NOV 14, 2013: A little additional googling indicates that "Harris Moore" is a pseudonym for Arthur Moore and Alf Harris. An Alf Harris wrote scripts for TV shows during the period in question.]
Lieutenant Slater is an officer on a space ship on a mission to find alien life. The head of the mission is Doctor Hadley, who has direct command over a team of scientists, while the ship and its crew are commanded by Captain Banyon. The ship has been away from Earth for five years, and has discovered no alien life whatsoever. The crew, desperate to get home, is ready to mutiny. Slater, during one of those periods he is on the bridge and not in his cabin enjoying the company of one of the female space travelers (he seduces two different women in the first 18 pages of the book), spots a planet which is quickly named after him, and which becomes the subject of intense investigation.
It turns out that the planet has no organic life and is run by two computers who study the humans as avidly as the humans are studying them. In a memorable scene the computers capture a female astronaut and dissect her. When the computers find themselves unable to reassemble and reactivate the woman, they put the pieces in a tub and return them to the Earthlings, hoping they will be able to put the woman back together and start her up again.
Slater makes contact with the computers, and acts as liaison between them and the humans. The computers ask for help: a comet is about to hit the planet and destroy it, and even though the computers detected this comet centuries ago they haven’t yet come up with any way to stop it. Maybe the humans and their space ship can save them? The Earthlings had better think fast, as the comet is due in two days, and the computers have disabled the ship’s atomic drives, preventing their escape.
Slater’s Planet is unambitiously and amateurishly written, full of minor mistakes and oddities. The astronomy is distractingly bad – Slater spots the planet (we are told because of its “high albedo,”) long before he detects the star the planet orbits. The word “galaxy” is sometimes used when I’d expect “solar system.” On the other hand, the main plot is not bad, and the second half of the book, when the two computers are competing with each other over the space ship using telepathy, robots, and holograms, and Captain Banyon leads a commando raid into the vast inner workings of the mechanical planet, generates some interest and tension.
Slater’s Planet is a borderline case. If the thing had gone through another edit to fix the distracting problems I would probably give it a marginal thumbs up as a simple fun adventure story, but as it stands I have to judge it poor.