John "The Penguin" Bingham writes a column for Runner's World magazine and teaches the basics of running to adult-onset athletes. The author of No Need for Speed and coauthor (with Jenny Hadfield) of Marathoning for Mortals, he lives in Chicago.

Jenny Hadfield, MA, CPT, is a fitness expert who has trained thousands of walkers, run-walkers, and runners of all levels. Her gentle yet uncompromising approach to training combined with her unique insights into the human body and mind will help readers discover their inner long-distance athlete. She lives in Chicago.