PDF versions of this roleplaying game have been released by Pelgrane Press. Now in addition to the hardback book, Trail of Cthulhu is available as a PDF of the full game, in a Player’s Guide version containing all non-GM material, and in a Game Group bundle of one full book and three Player’s Guides. Trail of Cthulhu uses the GUMSHOE system for investigative roleplaying in the world of Lovecraft’s literature.