MARK LAUREN spent 15 years as a military physical-training specialist. Now a personal trainer to civilian men and women of all fitness levels, a triathlete, and a champion Thai boxer, he is the author of the internationally popular body-weight bibles You Are Your Own Gym, Body by You, and Body Fuel.
JOSHUA CLARK has served as a correspondent for NPR, and was an editor for SCAT Magazine. He also created and co-authored the international bestseller fitness books You Are Your Own Gym and Body By You.