For her latest novel, Anne Tyler says she wanted to write a book that starts from the present and goes back in time so she’d never have to finish. That’s because, for Tyler, the best part of writing is when she’s in the middle. But even this book had to end and the result is her 20th novel. Set in Baltimore, “A Spool of Blue Thread” explores three generations of the Whitshank family. Over time, they’ve come to define themselves by certain family stories — and buried many others away in secret. In her first live radio interview, Pulitzer Prize winning author Anne Tyler joins Diane to discuss her new book and long career writing about matters of the family.