In 1983, while Larry DiTillio was on strike from his job as a television and movie screenwriter,:37 he was hired by various game companies to write role-playing adventures. One such assignment was Masks of Nyarlathotep for Chaosium, which he co-wrote with Lynn Willis.:38 It was published the same year.
In 1996, the campaign was revised, expanded and re-released as The Complete Masks of Nyarlathotep.
Masks of Nyarlathotep is a boxed set adventure that includes a 160-page perfect-bound softcover book (1983 edition), as well as a variety of handouts given to the players at various points; these include newspaper clippings, handwritten letters, business cards and a matchbox.
An edition published in 1990 added eight color plates of scenes from the adventures rendered by Nick Smith, Keith Berdak, Tom Sullivan, and Mark Roland, as well as full color cover art by Lee Gibbons. In the 1996 revision, The Complete Masks of Nyarlathotep, the handouts are printed on the pages of the new edition, meaning the gamemaster has to photocopy those pages in order to give the players the handouts at the appropriate times.
The campaign is a series of five sequential adventures that pit the investigators against Nyarlathotep, the Crawling Chaos and Outer God:
- The first adventure is set in New York, where the Investigators are drawn into the campaign by a gruesome death.
- Following clues, the Investigators move to London, seeking information both on a mysterious cult, and the ill-fated Carlyle Expedition.
- The Investigators move to Cairo, where they follow various clues, some of them red herrings.
- The fourth chapter is set in and around Nairobi, as the Investigators try to discover how the Carlyle Expedition came to an end.
- The last chapter takes the Investigators to Shanghai, where they must put all the clues together to bring a dangerous threat to an end.
In the May-June 1985 edition of The Space Gamer (No. 74), Matthew J. Costello was impressed, saying "The project is, in sum, massive and largely successful. Perhaps only TSR's Dragonlance series rivals it in size. And while some flavor may have escaped from this ghoulish stew, there's much here to delight Keepers, Investigators, and admirers of H.P. Lovecraft."
In the November 1985 edition of White Dwarf (Issue #71), Phil Frances lauded this book as "undoutedly the finest... supplement to come from Chaosium." Frances believed the series of adventures presented several possible problems, including a plot that was too complex for beginning gamemasters, and the high mortality rate among adventurers due to the extremely deadly adversaries. He concluded by giving it an excellent rating of 9 out of 9, saying "Masks Of Nyarlathotep is an adventure that is fun for both sides to play... This is the best campaign I have ever seen, from Chaosium or other sources."
In the June 1990 edition of Dragon (Issue 158), Jim Bambra called this book "some of the most powerful and deadly adventures ever written." Bambra lauded the "superb narrative and the tantalizing clues [that] carry the Investigators along at a cracking pace." He concluded, "Masks of Nyarlathotep is the epitome of COC adventures. It contains detective work, action, and indescribable horrors in all the right quantities. The writing and editing are first class; the adventures perfectly capture what COC is all about. No one should be without a copy of Masks of Nyarlathotep."
According to game historian Shannon Appelcline, Masks of Nyarlathotep is considered by many critics to be one of the best roleplaying adventures of all time.:86
- Shannon Appelcline (2011). Designers & Dragons. Mongoose Publishing. ISBN 978-1-907702-58-7.
- Bambra, Jim (June 1990). "Roleplaying Reviews". Dragon. Lake Geneva, Wisconsin: TSR (#158): 88-89.
- Winninger, Ray (July 1998). "Role-playing Reviews". Dragon. TSR, Inc. (249): 109–110.
- Frances, Phil (November 1985). "Open Box". White Dwarf. Games Workshop (71): 7–8.
- Costello, Matthew J. (May–June 1985). "The New Call of Cthulhu Adventure: Masks of Nyarlathotep". Space Gamer. Steve Jackson Games (74): 14.