Only on the "CBS This Morning" podcast, author Lisa Grunwald shares what inspired her latest historical fiction novel, "Time After Time." She shares why she decided to use one location as the sole backdrop for the novel and why the writing process took seven years. Talking with CBS News' chief medical correspondent Dr. Jon LaPook, Grunwald provides some history of Grand Central Terminal, including CBS News and Walter Cronkite's connection to the transportation hub. Plus, they discuss the similarities Grunwald shares with her main character and how a Frank Sinatra sound inspired the book's title.