One of the themes that I notice in the novel is generosity. Frank har escaped a mental hospital and the first man he meets invites him in and gives him clothes, food and even money. One would expect the man to be afraid of the stranger and send him away, but he is not afraid and gives Frank a helping hand. This shows great generosity. Later in the novel Frank meet another man who shows similar hospitality. The two meet at a cafe, and the man invites Frank home to his wife and children after only a short conversation. The man, Billy, understands that Frank needs a place to stay overnight and offers him to stay. I believe therefor that generosity is a central theme in the novel.
Another theme...