Who wouldn't want to earn money while playing? In fact, there are people who make a living by playing so-called Massive Multiplayer Games. Some have even managed to become dollar millionaires! You might be surprised to learn that the calculated gross domestic product of virtual worlds is higher than that of most countries on Earth, and that players of online role-playing games (if they were to sell their virtual goods for real money) would earn a higher hourly wage than, for example, a citizen from Russia. Astute entrepreneurs have recognized the value of virtual worlds and have created companies and online exchanges to sell virtual items for a high price. You may be wondering how all of this is possible! This book will show you the connections between virtual and real economies and explain the workings, dimensions, potentials, and dangers of virtual markets.