Joseph Papalia is an official historian of the 509th Composite Group, the US Army Air Force unit created specifically for dropping atomic bombs during World War II.
Papalia, who served in the Air Force in the 1950s, became interested in the 509th later in his life. He began attending 509th reunions, held annually, and became friends with many veterans of the group, as well as with other historians who focused on the unit.
His collection of more than a dozen interviews and oral histories with members of the 509th, the 509th Composite Group Collection, is available here.