21st Century Game Design is not just a book about game design. It's an answer to two important questions: who are we designing games for and how do we do it best? Written by industry pros, the book teaches designers how to design better games from a why perspective. All good designers know the fundamentals of how to design a game, but learning to design games that really satisfy your players takes more than technical skill. To do this successfully, you need to know your intended audience and understand their needs. Throughout the book you'll learn about defining and investigating player needs. A model of play styles is then presented that was developed by applying psychological metrics to survey data and case studies. This model identifies some of the core themes in player needs as represented by four player types-- Conqueror, Manager, Wanderer, and Participant. In addition to discussing player needs, the book also explores how games can reach wider audiences by appealing to the interests of the core gaming community, and it considers the fundamental principles of game design. Methods such as interface design, structural elements, and game world abstractions are discussed in relation to the needs of the audience. The book does not attempt to present an absolute view of the craft of game design, but rather it demonstrates how an audience model can inform the design process and take the games industry forward at a time when it is facing a schism between the games that the audience would like to play, and the games the development community would like to make. Game designers, producers, marketing executives, and anyone who wishes to understand the relationship between a game and its audience will find much to learn from 21st Century Game Design.