One of the major themes of "A Glass of Milk" is loneliness or isolation. The main character in the short story has no name. He has the opportunity to ask for food from the other dockworkers or people on ships but will not do it. It is only when he is near starvation that he asks a woman in a restaurant for a glass of milk, and then only after all the patrons have left for the evening. After he has eaten, he remains alone as he walks along the dock and finally sleeps. Rojas is illustrating that for many people, poverty and need can be very isolating.