Book excerpt: Sociologists disagree not only on how best to define "class" but also as to its general role in social theory and continued relevance to sociological analysis. This book explores the theoretical foundations of six major perspectives of class through the contributions of experts in the field. While some assume that classes have largely dissolved, others believe class remains one of the fundamental forms of social inequality and social power. Moreover, some see class as a narrow economic phenomenon, while others adopt an expansive conception.