This book presents a coherent research agenda that has been pursued by the author and his research group. The book opens with descriptions of the project and its methodology, as well as situating this research in the past and present context of the CSCL research field. The core research team then presents five concrete analyses of group interactions in different phases of the Virtual Math Teams research project. These chapters are followed by several studies by international collaborators, discussing the group discourse, the software affordances and alternative representations of the interaction, all using data from the VMT project. The concluding chapters address implications for the theory of group cognition and for the methodology of the learning sciences.