Dr. Crook received his medical education and training at the University of Virginia, The Pennsylvania Hospital, Vanderbilt and Johns Hopkins. He was a Fellow of the American Academy of Pediatrics, the American College of Asthma, Allergy and Immunology and the American Academy of Environmental Medicine and the American Medical Association. He also served as a Visiting Professor at Ohio State University, the University of California at San Francisco and the University of Saskatchewan.

His willingness to listen, learn and work with patients brought this revered pediatrician adult patients as well. Always open to new information and ideas, he became interested in adults' chronic health complaints connected to yeast overgrowth and to nutritional and environmental factors. In addition to yeast-related health problems, he spoke passionately about the role of nutrition in children's hyperactivity and learning disorders.

The author of 14 books and numerous articles in medical and lay literature, Dr. Crook addressed professional and lay groups in 39 states and eight countries. For 15 years, he wrote a nationally syndicated health column for General Features and Los Angeles Times syndicates and was a popular guest on national television and radio programs, along with the BBC and other international networks. Many of his publications have been translated into French, German, Japanese and Norwegian.

Dr. Crook's self-effacing manner and his genuine desire to help people suffering with chronic conditions earned him friends throughout the world. While his theories were often criticized, his professionalism earned him the respect of colleagues worldwide.

The father of three daughters, Dr. Crook lived and practiced medicine in Jackson, Tennessee for almost 40 years. He had compiled most of the manuscript for The Yeast Connection and Women's Health before his death in October 2002.