Letterman had a historic career in late night, from enfant terrible to elder statesman. If there's a bold idea with My Next Guest, it's to be as un-bold as possible. I mean that as a compliment. Letterman walked onstage, introduced his guest, and they sat down for an hour. A couple times, we cut to another conversation: The host crossing Selma's Edmund Pettus Bridge with Congressman John Lewis, a walk-and-talk guided tour of one of the true awe-inspiring moments in American history.