Reality and illusion
Reality and illusion are prominent themes in Death of a Salesman. The play uses flashbacks to present Willy's memories, but it is unclear whether they are accurate. He makes up lies about his and Biff's success. The more he indulges in the illusion, the harder it is for him to face reality. Biff realizes the problem and wants to face the truth. In this conflict, the play shows how the American Dream can be a lie.
In several statements, Miller compared the play's characters to Greek tragedy. The American playwright wanted to show that the common man and those with status had much in common.
Writing in The New York Times in 1999, journalist John Tierney argued that the play was not constructed like a classical tragedy. He observed that the mental illness suffered by Loman was a "biochemical abnormality" that was "not the sort of tragic flaw that makes a classic play." But he noted that "Willy's fate is supposed to be partly a result of his own moral failings, in particular the adulterous affair [...], he is haunted by the memory of his infidelity and by the fear that it ruined his son's life."