I am a retired physician epidemiologist who graduated from Vanderbilt University medical school in 1970 and from the University of Washington School of Public Health in 1975. My training in preventive medicine, started with 2 years in the U.S. Army as a preventive medicine officer, and has emphasized disease prevention of disease. Physicians typically learn little about prevention in medical school. Rather treatment of already established disease is emphasized. However, many studies have documented that preventing disease is always less expensive than disease treatment. Although the current level of understanding of all diseases is not yet at a point where prevention is always possible, for many diseases, proven prevention methods do exist. I have tried to emphasize this point in my books.