As David Letterman made his return on Howard Stern as well as prepping for a new show on Netflix, Kevin Lockett talks to New York Times writer Jason Zinoman in his book: Letterman, The Last Giant of Late Night. During their conversation, Kevin and Jason discuss how Dave's dad was a major influence on his comedy career, The underrated importance of Merrill Markoe on Late Night . How his heart bypass impacted Letterman's openness on TV and Jay Leno's use of the word "kindness." Before any this, the conversation starts with a look at former Letterman guest, Dave Chappelle. Be sure to follow Jason at @Zinoman on Twitter.