From Chaosium's Website: Call of Cthulhu is, of course, an excellent role-playing system and one that easily lends itself to expansion in many areas. In keeping with that spirit, this book explores a number of optional expansions to the original Call of Cthulhu rules—primarily in the areas of new, specialized skills; new spells, books, and magical artifacts; and new (or expanded) insanities to inflict upon hapless Investigators. It also introduces a few new Mythos creatures for your playing enjoyment (for those of you who actually like dying horribly or ending up gibbering insanely in a asylum), along with several NPCs to complicate your Investigators’ lives. Guidelines for creating psychic vampires in the game are also included, as is a sample vehicle and a few other tidbits. These optional additions to the game may also be used as desired with the various supplements to CoC, including Cthulhu by Gaslight and Pulp Cthulhu, and can be fit quite nicely into most eras of the game, from the 1890s through the 1920s and on into today. (And some may even be adaptable to Dreamlands, Dark Ages, and other settings or time periods, albeit with additional work on the part of the keeper.)