What does Steinbeck say about loneliness in Of Mice and Men?

In John Steinbeck's novel Of Mice and Men, which is set in Depression era America, loneliness is a central theme around which many characters revolve:

• Curley's wife: Despite the fact that she is married, Curley's wife feels neglected and lonely. She tries to combat this by flirting with the men and introducing drama into her life. Her loneliness is emphasized by the fact that no one knows her name (she is only ever referred to as Curley's wife), making her figuratively completely anonymous and alone. 


• Candy and his dog: Candy agrees to have his dog, which is old, sick, and in the process of dying, put down by other men at the ranch. Candy's hesitance, up to this point, has been rooted in loyalty, love, and the fear of loneliness. Candy, the only black man on the ranch, is also isolated; although he is surrounded by other ranch hands, he has no close friends, hopes, or dreams until George and Lennie arrive. 

These two examples, and there are many more in the text, prove that loneliness is not the result of being alone, but it is the result of having no close personal connections or experiences of empathy. Solitude does not have to be lonely, and one can feel isolated in a room full of people.