Lorraine Hansberry’s A Raisin in the Sun

Lorraine Hansberry prefaces her play with the poem "Harlem" by Langston Hughes. How does the play illustrate the theme of the poem? In what way is the concept of the "dream" central to the play? Which characters specifically discuss their dreams? What is Mama's dream in life? Ruth's? Walter's? Do dreams ever become destructive, a substitute for action? Or is it absolutely essential to keep a dream alive? Can you personally relate to having a dream deferred?