This chapter provides an overview of internet infidelity as an emerging yet widely practised phenomenon. The rise of social media as well as technological advancements that create “real” experiences online have made it possible for people to engage in multiple kinds of online relationships. Internet infidelity provides a new challenge to couples seeking to establish and maintain both emotional and physical intimacy. This book provides an interdisciplinary and coherent perspective of internet infidelity and its impact on relationships. This chapter end by providing an overview of the all the contributions in this volume. This book is ideal for marital therapists, counsellors, criminologists, legislators, researchers and students.