 He began working on the fourth edition of Chaosium's "Call of Cthulhu" role-playing game in 1989; he was the line editor for the game for the next five years, including the change to the fifth edition of "Call of Cthulhu" in 1992, until he left Chaosium in 1994.While there he wrote and edited such award-winning books as "The Fungi from Yuggoth", "Trail of Tsathogghua", "Spawn of Azathoth", "Arkham Unveiled", "Return to Dunwich", "Investigator’s Companion" Volumes 1 & 2, and the "Keeper’s Compendium".The anthology Cthulhu's Dark Cults was dedicated to his memory.