The research programme known as Studies of Expertise and Experience (SEE), often referred to as the “Third Wave of Science Studies,” treats expertise as real and as the property of social groups. This chapter explains the foundations of SEE and sets out the theoretical and methodological innovations created using this approach. These include the development of a new classification of expertise, which identifies a new kind of expertise called “interactional expertise,” and the creation of a new research method known as the Imitation Game designed to explore the content and distribution of interactional expertise. It concludes by showing how SEE illuminates a number of contemporary issues such as the challenges of interdisciplinary working and the role of experts in a “post-truth” society.