In this chapter, we introduce the reader to the project Faculty Peer Mentoring in Teaching and Supervision (PeTS). This project empirically documents how peer group mentoring practices have been implemented and experienced in four different academic settings at a research-intensive Nordic university. This introductory chapter begins by defining the conceptual basis for the PeTS project, presenting peer group mentoring (PGM) as a term to describe an activity providing collaborative spaces for academic staff to discuss their teaching and supervision practices for the purpose of professional development. The chapter continues by presenting a review of research on PGM internationally, which we relate to the two mentoring models that are implemented and studied in the PeTS project. The chapter also describes how these implementations are studied, here based on an overarching research design. With these conceptual and methodological grounds, this introduction aims to provide a common basis for the subsequent contributions of the book. The introduction also serves as a foundation for final reflections and conclusions in the last chapter, where the overarching aim of the current publication is related to international research, providing commentaries from respected scholars within the field of higher education and faculty development.