Computer games have become ubiquitous in today's society. Many scholars have speculated on the reasons for their massive success. Yet we haven't considered the most basic questions: Why do computer games exist? What specific circumstances led to the creation of this entirely new type of game? What sorts of knowledge facilitated the requisite technological and institutional transformations? With Computer Game Worlds, Claus Pias sets out to answer these questions. Tracing computer games from their earliest forms to the unstoppable commercial and cultural phenomena they have become today, Pias then provides a careful epistemological reconstruction of the process of playing games, both at computers and by computers themselves. The book makes a valuable theoretical contribution to the ongoing discussion about computer games.