Class is not only amongst the oldest and most controversial of all concepts in social science, but also a topic which has fascinated, amused, incensed and galvanized the general public. But what exactly is a 'class'? How do sociologists study and measure it, and how does it correspond to everyday understandings of social difference in the twenty-first century? In a time when inequality has dramatically returned to the social scientific and political agenda, this accessible and lively book explores these questions and more. It takes readers through the key theoretical traditions in class research, the major controversies that have shaken the field and the continuing effects of class difference, class struggle and class inequality across a range of domains. This new edition covers the latest research and scholarship and includes extended discussions of race, the rise of national populism, and the reconfigurations of class in a global age. This book will appeal to students and scholars across the social sciences, and anyone wanting to get a handle on this provocative concept.