A social category that on the one hand acknowledges a shared state of affairs amongst a large group of people whose material conditions are very similar and on the other hand recognizes that significant and real differences do exist between groups. From the perspective of their material conditions (i.e. how much money they have at their disposal, the kinds of houses they can afford, and so on), the group of people who are either unemployed or underemployed have more in common with each other than they do with professional people, who are better paid and have greater financial security. Therefore the unemployed or underemployed constitute one class and the professionals constitute another class. This concept is central to Marxism, although Marx, Karl himself did not invent the term, nor did he ever provide a satisfactorily complete definition. On Marxâs understanding, class is an essentially antagonistic concept: it defines not merely lines of difference, but lines of struggle. The history of class, Marx famously said, is the history of class struggle. Class is not simply a matter of the passive membership of a group. Marx assumes that classes arise out of a sense of common interest born of a common situation and a common idea of who the enemy is, or what he terms class consciousness. When it is said, as it sometimes is (especially by the right wing), that class no longer exists and that we live in a classless society, it is in fact class consciousness that is at issue, not class itself, which as an economic category is manifestly still with us. In this respect, it is crucial to note that Marx connected class to his concept of the mode of production, arguing that classes are defined according to the relationship to the means of production. Do they own the means of production or not? That is the essential question for Marx, who using that metric identified three basic classes: the proletariat (wage earners who have nothing but their labour to sell), bourgeoisie (the owners of the means of production, or capitalists), and land-owners (rentiers). Viewed in this strict fashion, the professional class (inasmuch as they do not own factories, but receive wages) are closer to the unemployed or underemployed than they are to bourgeoisie, even though they may share the latterâs cultural tastes and habits. This is a problem Bourdieu, Pierre addresses in his concept of habitus. As Marx conceived it, class crosses all geographical boundaries---the proletariat are the same whether they are based in America or Asia---and it was always his hope that the workers of the world would recognize their common situation and unite and together overthrow the capitalist class. A similar vision animates Hardt, Michael and Negri, Antonioâs concept of multitude. Further Reading: A. Milner Class (1999).