What is the theme in House of Sand and Fog by Andre Dubus III?

Appearances and realities is a theme in the story. The novel though begins with Behrani living a double life: he leaves home well dressed-then changes clothes and goes to work picking up trash for the Highway Department by day, acting as a convenience store clerk by night...then he changes back and returns home well dressed. His wife Nadi thinks that maintaining the appearance of wealth is essential to their daughter's finding a wealthy husband (indeed, such a marriage occurred shortly before the novel begins). Kathy also tries to keep up appearances by not telling her mother that Nick has left her, pretending that everything is fine, which in a way she thinks it is, when she and Lester fall in love-but things are certainly not all right in the way she leads her mother to believe.