Sociology of classes of Michele Lamont, which was developed in a dialogue with Pierre Bourdeu’s theory of classes, is a separate and original proposal of studies on classes. It is to be based on analyses of group identification articulation that are used by actors for self-defining, but at the same time also imply the process of defining and drawing symbolic boundaries between classes. However, these boundaries tend to differ from the boundaries defined in the analyses of economic resources and the social and demographic diversity. Lamont creates and develops her theory against two major challenges that theories of classes face: international comparisons which would focus on cultural distinctions and avoid methodological nationalism, similarly to Bourdieu’s theory. The second challenge would be the forms of social diversity, which are not likely to occur in class analyses, such as racial or gender diversity, and seem to be essential to understand contemporary diversity of societies.