Mark Atwood Lawrence is an award-winning historian who's taught for two decades at the University of Texas at Austin. He is the Director of the LBJ Presidential Library. His books include The End of Ambition: The United States and the Third World in the Vietnam Era, which won the highest book award from the Society for Historians of American Foreign Relations.
Mark K. Updegrove is a presidential historian for ABC News and author of five books on the presidency, including most recently Incomparable Grace: JFK in the Presidency. He is a former director of the LBJ Presidential Library and now serves as President and CEO of the LBJ Foundation.