Dr. Jeffrey S. Bland is known as the "father of functional medicine," and over the past thirty-five years has taught more than 100,000 health-care practitioners around the globe. He has been a university biochemistry professor, a research director at the Linus Pauling Institute of Science and Medicine, the cofounder of the Institute for Functional Medicine in 1991, and the founder/president of the Personalized Lifestyle Medicine Institute. He lives in Seattle, Washington, with his wife, Susan, and near his three sons and their families.

Dr. Josh Axe is a board-certified doctor of natural medicine (DNM), a doctor of chiropractic, and a certified nutritionist from the American College of Nutrition. He is the founder of DrAxe.com, one of the most visited natural health sites in the world.