Over the years I’ve been part of various book groups. Typically, several friends read a book and then we get together to discuss the ideas the author has put forward. Inevitably, one person will raise a question that none of us can answer. And then someone will say, “If only we could ask the author.” A popular new trend in New York City is making that possible. Some authors, for a hefty fee, are making themselves available to meet with book clubs.