Chris Crowley, a former litigator (Davis Polk & Wardwell), is the coauthor, with Henry S. Lodge, of the Younger Next Year books, and the coauthor, with Jen Sacheck, PhD, of Thinner This Year. Though in his eighties, he fully lives the life, skiing black diamonds and routinely doing thirty-mile bike rides. He and his wife live in Connecticut and New York City.

Allan J. Hamilton, MD, FACS, a Harvard-trained brain surgeon, is the executive director of the Arizona Simulation Technology and Education Center. Dr. Hamilton has authored more than 20 medical textbook chapters and 50 peer-review research articles, and has served on the editorial board of several medical journals. He is the author of The Scalpel and the Soul, Zen Mind, Zen Horse, and Lead with Your Heart. He lives near Tucson, Arizona.

Allan J. Hamilton, MD, is a Harvard-trained brain surgeon, a renowned horse trainer, a developer of equine-assisted learning programs, and the author of Lead with Your Heart and Zen Mind, Zen Horse (Gold Nautilus Award winner). He is a professor of neurosurgery at the University of Arizona and a medical script consultant for the hit television series Grey's Anatomy. He raises Lipizzan horses on a small ranch on the outskirts of Tucson, Arizona.