Ever since the emergence of sociology as a discipline, sociologists have shown an interest in paid work. Marx, Weber, and Durkheim’s interest in societal changes was inspired by the rise of market relations and paid work. The classical sociologists studied the growth and spread of paid work in relation to the development of inequality, rationalization, and social cohesion. Since then, the form and content of employment relationships has changed substantially and keeps on changing. The continued interest of sociologists in these developments has culminated in a well-established field of research. This article explores that field of research in three parts. The first part of the bibliography lists textbooks, reference manuals, journals, and national research traditions. The field shows substantial variety due to the constant development of the labor market and employment relations, and due to institutional differences in the architecture of employment relations. The second part of the article focuses on developments in paid work. The following themes are explored: the growth of paid work relationships, the increase in the number of paid work hours, the major changes in the architecture of employment relationships, the effects of paid work relationships on the well-being of workers, and the development of work values and work-hour preferences. The third part focuses on different labor market positions. This section starts with the standard employment relationship and then moves on to its counterpart: unemployment. It continues with workers in nonstandard positions, such as temporary jobs, part-time jobs, jobs with irregular and long work hours, and self-employed workers.