This chapter serves as a general introduction to the research theme of the dissertation and delineates the context in which the subsequent chapters of this dissertation are situated. The first section of this chapter presents the general theoretical background. First, school factors, with special attention to professional learning communities, and contextual factors are presented. Second, teachers’ psychological states and outcomes are discussed. Following this, the problem statement is set down and transformed into specific research objectives. Furthermore, information on the overall research design is presented. At the end of this chapter, an outline of this dissertation and an overview of the content of the different chapters is provided.