The induction phase - encompassing the transition from teacher education to the professional practice and the first years in the job - is one of the most challenging career phases for teachers. Many teachers experience this phase as problematic and even decide to leave the teaching job within the first years. This research project argues that the persistence of this problem is at least partly due to the way it has been framed conceptually and methodologically. The project emphasizes teacher induction as an important phase for fundamental research and theory building on teacher professional development. As such, this project aims at deepening and refining theory development by addressing teacher induction from an innovative theoretical and methodological perspective, grounded in social network theory. The project wants to study how, under which conditions, and with what impact, beginning teachers develop professional networks with relevant actors during their first year at school. A central focus of the project is on how beginning teachers develop professionally, and how they learn about the social, cultural and political life of and in a school network. Research questions will be answered through two complementary research designs: a repeated measurement survey and a multiple case study research. Social Network Analysis (SNA) is a key feature in these designs and implies a focus on understanding the nature and consequences of ties between individuals and groups.