Octagon is a novel by Fred Saberhagen published in 1981.
Greg Costikyan reviewed Octagon in Ares Magazine #11 and commented that "Octagon is a good mystery novel which explores a rather interesting theme: the idea that a clever programmer can manipulate records and programs in our computer-based world to his own ends."
Dave Langford reviewed The Flight of the Dragonfly for White Dwarf #68, and stated that "it's a pleasant thriller with the computer-moderated RPG Starweb getting uncomfortable as players are eliminated not by strategy but by assassination. I recommend this technique to Diplomacy addicts. The villain's identity is obvious long before the story reveals it, but it's all quite tense nevertheless."