Game mechanics--the rules and systems that govern the functional behavior of a game--lie at the heart of all game design. The mechanics implement the living world of the game; they generate active challenges for players to solve in the game world and they determine the effects of the players' actions on that world. Here to teach game designers and students the essentials of game mechanics are two leading authorities in game design. Readers will learn how to craft mechanics that generate challenging, enjoyable, and well-balanced gameplay. They'll learn how to visualize and simulate game mechanics in order to design better games and learn at what stages to prototype, test, and implement mechanics in games.This in-depth resource also comes with hands-on lessons and readers can download a free simulation tool in order to follow along with exercises in the book.