How does A Raisin in the Sun transcend the label "minority literature"?
This dramatic work represents an ethnic group but it also deals with universal themes such as friendship, trust, betrayal, loss, hope, disillusionment, etc. Everyone can relate to it in some way. Also, it is a well-balanced, cohesive "vignette" of a lower class American family. The protagonist is not a super-hero but an ordinary "everyman" type, dealing with his problems somewhat unsuccessfully:
Despite an incredible number of imperfections, Raisin is a good play. Its basic strength lies in the character and the problem of Walter Lee, which transcends his being a Negro. If the play were only the Negro-white conflict that crops up when the family's proposed move is about to take place, it would be an editorial, momentarily effective, and nothing more. Walter Lee's difficulty, however, is that he has accepted the American myth of success at its face value, that he is trapped, as Willy Loman was trapped, by a false dream. In planting so indigenous an American image at the center of her play, Miss Hansberry has come as close as possible to what she intended—a play about Negroes which is not simply a Negro play.
- from enotes 'Thoughts on "A Raisin in the Sun" '
Because it deals with "the big issues" on a small scale, this play captures the essential in a diminuative way. It has both scope and concision - the mark of "a classic."