I doubt many presidential appointees have indirectly saved more lives or done more to change American culture for the better than C. Everett Koop, U.S. surgeon general under Ronald Reagan. Koop died today at the age of 96, a legend in the field of public health.

While Koop can’t claim sole credit for the sharp decline in smoking rates during the 1980s, his high-profile warnings drew more attention than ever to the dangers of using tobacco.

As surgeon general, he released a report in 1982 that attributed 30 percent of all cancer deaths to smoking. He wrote that nicotine was as addictive as heroin, warned against the hazards of secondhand smoke and updated the warning labels on cigarette packs.

Michael C. Fiore, founder of the University of Wisconsin Center for Tobacco Research and Intervention, once said Dr. Koop’s reports on smoking “totally changed the landscape” of tobacco control.

Koop also confounded the expectations of his patrons.

A 64-year-old retired pediatric surgeon at the time Ronald Reagan nominated him in 1981, Dr. Koop had no formal public-health training. His chief credential was that he was a socially conservative, devout Christian physician who had written a popular treatise against abortion. His confirmation took eight months. Few people expected him to talk about homosexuality, anal intercourse, condoms and intravenous drug use when almost nobody else in the Reagan administration would even utter the word “AIDS.”

Dr. Koop, however, believed information was the most useful weapon against HIV at a time when there was little treatment for the infection and widespread fear that it might soon threaten the general population. In May 1988, he mailed a seven-page brochure, “Understanding AIDS,” to all 107 million households in the country.

There must be thousands of people who are alive today thanks to Koop’s work during the Reagan administration, not counting all the children he helped to save as a pediatric surgeon. In my opinion, he was Reagan’s best appointee by far. May he rest in peace.