With his striking beard and starched uniform, former Surgeon General C. Everett Koop became one of the most recognizable figures of the Reagan era -- and one of the most unexpectedly enduring.His nomination in 1981 met a wall of opposition from women's groups and liberal politicians, who complained that President Ronald Reagan selected Dr. Koop, a pediatric surgeon and evangelical Christian from Philadelphia, only because of his conservative views, especially his staunch opposition to abortion.Soon, though, he was a hero to AIDS activists, who chanted "Koop, Koop" at his appearances but booed other officials. And when he left his post in 1989, he left behind a landscape where AIDS was a top research and educational priority, smoking was considered a public health hazard, and access to abortion stayed largely intact.Dr. Koop, who turned his once-obscure post into a bully pulpit for seven years during the Reagan and George H.W. Bush administrations and who surprised both ends of the political spectrum by setting aside his conservative personal views on issues such as homosexuality and abortion to keep his focus sharply medical, died Monday at home in Hanover, N.H. He was 96.An assistant at Dr. Koop's Dartmouth College institute, Susan Wills, confirmed his death but didn't disclose its cause.Dr. Richard Carmona, who served as surgeon general a decade ago under President George W. Bush, said Dr. Koop was a mentor to him and preached the importance of staying true to the science even if it made politicians uncomfortable."He set the bar high for all who followed in his footsteps," Carmona said.Although the surgeon general has no real authority to set government policy, Dr. Koop described himself as "the health conscience of the country" and said modestly just before leaving his post that "my only influence was through moral suasion."A former pipe smoker, Dr. Koop carried out a crusade to end smoking in the United States; his goal had been to do so by 2000. He said cigarettes were as addictive as heroin and cocaine. And he shocked his conservative supporters when he endorsed condoms and sex education to stop the spread of AIDS.Chris Collins, a vice president of amFAR, the Foundation for AIDS Research, said many people don't realize what an important role Koop played at the beginning of the AIDS epidemic."At the time, he really changed the national conversation, and he showed real courage," Collins said.Even after leaving office, Dr. Koop continued to promote public health causes, from preventing childhood accidents to better training for doctors."I will use the written word, the spoken word and whatever I can in the electronic media to deliver health messages to this country as long as people will listen," he promised.