As part of its recent 100 Best Books of the 21st Century project, The New York Times Book Review is interviewing some of the authors whose books appeared on the list. This week, Jennifer Egan joins host Gilbert Cruz to discuss her Pulitzer-winning novel about the music industry, “A Visit From the Goon Squad,” and talks, among other things, about the early challenges it faced in finding an audience, the meaning of its title and her initial reluctance to decide whether the book was a novel or a story collection.