Over the last 20 years there has been an expansion of network mediated social activities, and an accompanying explosion of research interest into the poetics of networked communication. Of particular interest is the rise of what have come to be known as “virtual worlds”: persistent graphical environments populated (and often partially authored) by large communities of individual users. Interactors in these worlds are embodied as avatars: digital puppets or representations through which the user exerts his or her will on the environment. It is this virtual embodiment that makes today’s virtual worlds so interesting. With virtual embodiment comes a host of new and important communicative possibilities, and an assortment of new challenges and literacies including a wide range of nonverbal communication behaviors and non-linguistic social signaling options. In this book, we begin the work of articulating the challenges and possibilities for non-verbal communication in virtual worlds. Drawing on a wide range of disciplines and perspectives, we consider the past, present, and future of human communication online. See Video Figures referenced in the text.