The main theme of A Streetcar Named Desire can be boiled down to one word: death. This is a play about endings: the end of Blanche's youth, the end of the Old South itself, and the end of Blanche's sense of identity as a charming southern belle. It is notable that Blanche comes to the Kowalski home after a period of burying her dead relatives. She has gone through the motions of moving on from the past, but ultimately cannot fully recover from her metaphorical deaths.
Death touches the other themes in the play as well, such as class conflict. Around the middle of the twentieth century, the Old South, represented by plantations and southern aristocracy, was giving way to a New South dominated by outsiders, represented in the play by the Polish-American and working-class Stanley. Blanche, with all her upper-class affectations and snobbery, has no place in the Kowalski household. She has been displaced from the old culture and has no niche in the new.
Sexuality is also linked with death. Blanche's husband—a closeted gay man—kills himself when Blanche catches him in bed with a male friend. Blanche's reputation is destroyed when she has an affair with a student and then prostitutes herself to young soldiers. These encounters lead to her desperate situation and her shaky place in the Kowalski house. Blanche seems to view unrestrained desire as a way of reclaiming her power in a world where she has none; seducing younger men allows her to control them on some level. However, at the end of the play, Blanche loses all control when Stanley rapes her. At this point, she suffers a final break with reality. In this way, Blanche suffers a psychological death and is only able to reclaim her lost identity in a state of madness.