The popular and often controversial thinker and novelist is dead of leukemia at age 71. Since she was Against Interpretation I'll avoid trying to give this passing any context. Newsday helpfully reprints a recent address Sontag gave, which fans may enjoy:
Literature is a form of responsibility—to literature itself and to society. By literature, I mean literature in the normative sense, the sense in which literature incarnates and defends high standards. By society, I mean society in the normative sense too, which suggests that a great writer of fiction, by writing truthfully about the society in which she or he lives, cannot help but evoke (if only by their absence) the better standards of justice and of truthfulness which we have the right (some would say the duty) to militate for in the necessarily imperfect societies in which we live.
Obviously, I think of the writer of novels and stories and plays as a moral agent. In my view, a fiction writer whose adherence is to literature is, necessarily, someone who thinks about moral problems: about what is just and unjust, what is better or worse, what is repulsive and admirable, what is lamentable and what inspires joy and approbation. This doesn't entail moralizing in any direct or crude sense.
Serious fiction writers think about moral problems practically. They tell stories. They narrate. They evoke our common humanity in narratives with which we can identify, even though the lives may be remote from our own. They stimulate our imagination. The stories they tell enlarge and complicate—and, therefore, improve—our sympathies. They educate our capacity for moral judgment.