Grant Blackwood, author of the Briggs Tanner series, co-author of the Fargo Adventure Series with Clive Cussler, co-author of the Tucker Wayne series with James Rollins, and co-author of Dead or Alive with Tom Clancy, talks to Sean Tuohy about his path to writing, his approach to Jack Ryan Jr. and the Tom Clancy universe in the recently published Duty and Honor, and why persistence is the key ingredient to being a successful writer.