The Monster Manual is one of the core books for playing Dungeons & Dragons in a creative and vibrant world. The book contains a baseline for all the different types of monsters and adversaries that characters may run into during their adventures. While other monsters have been added in later books. This book contains the stats for some of the most famous Dungeons & Dragons monsters as well as some of the more common creatures. There is no better resource for adding adversaries to a game than the Monster Manual.