The world of sociology seems to consist of two clearly separated areas: the realm of theory and that of empiricism. This is evident in the titles of university chairs, in job postings, and in the design of textbooks. One is either a theorist or an empiricist. The starting point of the contributions gathered in this volume is the practice of qualitative social research, representing an empirical tradition that has fundamentally changed the landscape of sociology over the past twenty years: it explores the life worlds of modern societies and presents them in a new light. In this volume, empiricists and theorists of sociology examine the tension and mutual interpenetration between theory formation and empirical research in order to redefine the relationship between theory and empiricism.