Of Mice and Men by John Steinbeck is set during the Great Depression and focuses on its economic effects on poor agricultural laborers. George Milton and Lennie Small are migrant laborers, both lacking the education to qualify for jobs other than work as farm hands. While George is intelligent and has some understanding of the world around him, Lennie, despite his impressive physical strength, is developmentally disabled, and although he has a childlike and affectionate nature much of the time, he is occasionally unable to control his strength.
The first example of their socio-economic situation is their inability to build up savings due to their extremely low wages. This means that their future, like that of the elderly Candy, is simply to keep working until they die. Although they dream of having their own small farm, they cannot afford it.
The second example we see of the social and economic position of the two men is that they are subject to vigilante justice. While in the wealthier urban areas of the east, there is the rule of law, in the poorer communities of California, actual or threatened vigilante justice seems omnipresent, and the legal authorities do not really seem interested in injustices affecting poor migrants.