Elson M. Haas, MD, is the medical director of the Preventative Medical Center of Marin in San Rafael, Calif. He is one of the nation's leading practitioners of integrative medicine. Haas's acclaimed books include Staying Healthy With Nutrition, The Detox Diet, A Diet for All Seasons, and Staying Healthy With the Seasons. He lives with his family on a farm in Sonoma County, Calif., where he grows many of his own healthy foods.