Murray, Robert K.: - Robert K. Murray (1922-2019) was professor of history at Pennsylvania State University for more than three decades as well as a senior fellow in the university's Institute for the Arts and Humanities. His work includes The Harding Era: Warren G. Harding and His Administration, The 103rd Ballot: Democrats and the Disaster in Madison Square Garden, and the coauthored book Greatness in the White House: Rating the Presidents--From George Washington through Ronald Reagan.

Brucker, Roger W.: - Roger W. Brucker is a lifelong cave explorer and cofounder of the Cave Research Foundation. He is coauthor of several books, including The Longest Cave with Richard A. Watson, and is also author of Grand, Gloomy, and Peculiar: Stephen Bishop at Mammoth Cave and Mama Says, Don't Cave: Ergor's Unbelievable Cave Stories (under the pseudonym Ergor Rubreck).