For that reason, it has nine chapters divided into three parts; playing on the "Master" in DMG, it divides the chapters into "Master of Worlds" (explaining how to create settings, with rules about maps, towns, campaigns, tiers, and different planes in the multiverse), "Master of Adventures" (explaining how to create and run adventures and NPCs, the different types of adventuring environments, treasure, and what happens between adventures), and "Master of Rules," (which has the ideas and rules for running the game, along with specialized rules, optional rules, and how rules can be modified).