A companion to the previously released Petersen's Guide to Cthulhu Monsters, it goes a bit farther afield with several entries from the works of Clark Ashton Smith, some from no obvious source (like the Blupe), and others essentially invented by Chaosium from brief mentions in "The Dream-Quest of Unknown Kadath." Unfortunately, several definitive Dreamlands Entities like moon-beasts and nightgaunts were covered in the first book and recieve only cursory mention here.

Like its predecessor, it features a annotated bibliography of mock-scientific works and a detailed key to distinguishing a Gug from a ghoul. Gorgeous full-color paintings are provided by Mark J. Ferrari.