I disagree with a negartive previous poster. This is an earlier work of Martin's yet bears simalr hall marks of his more famous later books: particualrly the way the main character is vain and selfish, yet you end up routing for him. It's a short story, so there is not much of a chance to develop the back-story of course. What is there though is extremely good though.
The atmosphere is oppressive and foreboding, and you do feel the fear of the main character. The main villain is creepy, and the stroy builds to a nice climax. I also liked the fact that as the main character exlpores abd makes some interesting discoveries, you are never told the answers to questions raised about the past and the origins of the Alien characters but are allowed to infer your own meaning.
For me it was a page-turner-which is always pre-requiste for a good book. Yes too short, but a good scary ride.