What has happened to the public intellectual? When Susan Sontag died in 2004, after losing her third battle with cancer, it seemed as though not only a majestic woman but a twentieth century tradition had died. Who in public life now has Sontag’s uncompromising verve, her endless curiosity, her willingness to plunge headlong into both intellectual theory and artistic practice?

Granted, during her lifetime Sontag could be the butt of jokes—and she could also be a bit of a pain. Her name was often invoked as a byword for “something intellectual you probably don’t understand,” used in movies from Bull Durham to Gremlins 2. She was tone-deaf after 9/11, insisting the hijackers had legitimate cause. Even the writer Wayne Koestenbaum, one of her most ardent fans, admits that “she represents grandiosity, I think, and it is a little comic…because it seems a bit of a pose.”

That quote, and many other revealing ones about Sontag, occur in Nancy Kates’ fascinating HBO documentary Regarding Susan Sontag (debuting Monday December 8), where we find out a lot about Sontag as both public figure and private individual. We learn about her huge intellectual appetite, her ambivalence about being gay and Jewish, and the beauty that made everyone from Henri Cartier-Bresson to Andy Warhol want to photograph her.