Amazon.com description: Product Description: While Mutants & Masterminds players create heroes, the Gamemaster creates the villains, the adventures, and the entire world where the series takes place. That can be a lot of work, but the Mutants & Masterminds: Gamemaster's Guide is here to help. This book has everything a M&M Gamemaster needs, from guidelines on creating challenges and adventures to advice on designing your own setting and series. The Gamemaster's Guide includes guidance on how to set up and run your game and to help your players create the best heroes, archetypes that make building villains easy, world-building tips, and options for modifying the game to suit your group's play style.