The fact that the Youngers are black now seems less like an innovation than a detail, though it's marvelous to see how precisely Ms. Hansberry caught the tone of black life in the 1950s.
His most recent book, "The Quality of Mercy, " is a sequel to "Sacred Hunger, " and while it is smaller and less ambitious than its predecessor, it is a marvelous story told in Mr. Unsworth's typically polished prose.