Guy Consolmagno is a Jesuit brother at the Specola Vaticana (Vatican Observatory), dividing his time between Tucson, Arizona and Castel Gandolfo, Italy. He studies the origin and evolution of moons and asteroids in our solar system and uses a 3.5'' catadioptic and an 8'' Dobsonian. He has been awarded the 2014 Carl Sagan Medal from the American Astronomical Society for outstanding communication by an active planetary scientist to the general public.
Dan M. Davis is a professor of geophysics in the Department of Earth and Space Sciences at Stony Brook University, New York. He researches the formation of mountain belts on Earth. His observations for this book were made with a 2.4" refractor and with 8" and 10" Dobsonians.