This book investigates the emerging phenomenon of the self as it exists in the online world. It argues for an externalist conception of self and identity, one that does not depend on the continuity of consciousness of the subject. It also offers an analysis of related phenomenon such as online friendship and games based on this analysis. An outstanding feature of social networking sites such as Facebook and MySpace is that it allows for the user to put forward their "selves" or their identity onto the Internet and use the online self as an anchor to connect with any number of "friends" each of whom also has their own online selves. A number of questions then arise which are deeply conceptual and philosophical in nature: What is the metaphysical nature of this emerging online self? Is it the same or fundamentally different from the "offline" self with which we are already familiar? Since increasing numbers of people are connected to the online world, this world itself seems to be taking on a reality of its own. This much has been appreciated by a number of scholars in the field. However, there seems to be lacking a systematic study of the philosophical and metaphysical nature of the self that has become a key element in cyberspace, a key topic which this volume addresses. Apart from the problem of constitution of the online self, this volume addresses related questions concerning personal identity in the online world and scrutinizes computer games and the characteristics that they share with social networking sites. Unlike the majority of the existing literature, which discusses the topic from a more social scientific perspective, this volume fills the lacuna of a philosophical and theoretical study of the online world.