Some famous writers were enjoying themselves at a party hosted by Michael Lewis in a lovely old house on the edge of Audubon Park. Susan Orlean was beginning to say her goodbyes. Anderson Cooper was milling about. Others gathered in clusters, talking shop over cocktails. The author Nancy Lemann preferred to be a bit apart from the din. She was sitting in a high-backed chair on the veranda, a glass of white wine beside her, watching night fall on the oaks.