On a bright and sweltering Sunday, I meet Williams at the three-story brownstone in Boerum Hill where she lives with her daughter, Matilda. Reminders of Heath Ledger, from whom Williams was separated when he died in 2008, are everywhere—in family photos, in the oversize stuffed animals that he bought for Matilda, in the large, brooding mountainscape by the Australian photographer Bill Henson that hangs in the living room. The most vivid reminder, of course, is Matilda herself, a spirited, sunny six-year-old whose face, a felicitous mix of both her parents, lights up when Williams walks into the room. “Supermommy!” she shouts, running to throw her arms around her mother’s waist. “Hiya, Superdaughter,” Williams says, kneeling down to kiss her forehead.