Title: Octagon
Description: From the back cover:

NICE GUYS FINISH DEAD!

It was a game.  That was all it was ever meant to be.  All the men and women, young and old, who paid their fees and took roles in the mail order STARWEB adventure had never had the slightest reason to suspect that they were letting themselves in for anything other than some harmless escapism, fighting imaginary battles on the immaterial killing ground of a computer's memory banks.

Then they began to dies.

Alex Barrow finds himself a not entirely willing participant in this grisly shadow war, drafted into it by his uncle, Bob Gregory, perhaps the only man who has any idea what is happening.  But Robert Gregory cannot reveal his suspicions to anyone -- because if he is right, then *he* is the murderer....
Subjects: American Science fiction, Fiction, general