'Teddy Ballgame' left baseball twice to serve his country. In Korea, he became friends with another soon-to-be famous Marine.

As a history professor at the U.S. Military Academy at West Point, N.Y., the career path of Greg Daddis, who has a doctorate in American history, couldn’t have been further from the movie business. However, after two executives visited the school on a research trip, the former Army armored cavalry colonel found himself part of the team for The Vietnam War, the latest project by noted documentarians Ken Burns and Lynn Novick.

Doug Nordman is different from most 56-year-old military retirees. For one thing, he hasn’t worked since he hung up his cover.