Sociologically speaking social stratification is a system of ranking of different categories of people in the society on the basis of hierarchy. It has been present all over the world since generations but it varies from society to society. When we study about social stratification we see that there are some groups who enjoy higher prestige, rank and wealth in the society than the others. This in turn causes social stratification in the society which creates inequality between the individuals and the groups.
In the field of social stratification when we study Thompson we notice that he sees class from a historical point of view and that he mentions one cannot study any class structure until he has referred to the history of it. He specially emphasizes on the 'working class' and their gradual emergence in the society. Thompson does not see class as a 'structure' or a 'category' rather he believes that it was emerged out of human relationships with time. Later Thompson even mentions that a class of a person is determined by birth and that it is involuntary. Here he is connecting a person's class to his birth which I slightly disagree with. I believe that class of a person can either be determined by birth or a person can acquire class. That is a person may be born in a middle class family but in the long run he may earn a lot of wealth and in turn become a part of the upper class society. .
Thompson even talks about class-consciousness where he again refers to history in order to understand its tradition, value system and its forms in the society there he mentions about the different types of classes in the society. He even mentions that class-consciousness varies from society to society. Whereas from Marx's point of view he divided the society into two important class that is the Bourgeoisie or the higher class group and the Proletariat or the lower class group and through these two classes he explained his views of class-consciousness.