In recent years a new trend in socio-cognitive research investigates into the mental capacities that allow humans to relate to each other and to engage in social interactions. One of the main streams is the study of intersubjectivity, namely the 'mutual sharing of experiences', conceived of as a basic dimension of consciousness on which socialness is grounded. At the very heart of contemporary studies is an intense debate around some central questions that concern the nature and forms of human intersubjectivity, its development and its role in situated joint activities.Striving to achieve a unified theoretical framework, these studies are characterized by a strong interdisciplinary approach founded on philosophical accounts, conceptual analysis, neuroscientific results and experimental data offered by developmental and comparative psychology. This book aims to give a general overview of this relevant and innovative area of research by bringing together seventeen contributions by eminent scholars who address the more relevant issues in the field.