This book is about the fastest growing form of electronic game in the world - the Massively Multiplayer Online Role Playing Game (MMORPG). It introduces these self-contained three-dimensional virtual worlds, often inhabited by thousands of players, and describes their evolution; it also delves into the psychology of the people who inhabit the game universe and explores the development of unique cultures, economies, moral codes, and slang in virtual communities. The work describes MMORPGs' ever-greater effect on society: for example, players can sell virtual goods for real money, creating a separate economy, and several governments have labeled the games a public health threat. It explains how the games are built, the spin-offs that players create to enhance their game lives, and peeks at the future of MMORPGs as they evolve from a form of amusement to an educational, scientific, and business tool. Based on hundreds of interviews over a three-year period, the work explores reasons people are attracted to and addicted to these games. It also surveys many existing and upcoming games, identifying their unique features and attractions. Two appendices list online addiction organizations and MMORPG information sites.