In 1976, a small group of soldiers at Fort Dix were infected with a swine flu virus that was deemed similar to the virus responsible for the great 1918-19 world-wide flu pandemic. The U.S. government initiated an unprecedented effort to immunize every American against the disease. While a qualified success in terms of numbers reached—more than 40 million Americans received the vaccine—the disease never reappeared. The program was marked by controversy, delay, administrative troubles, legal complications, unforeseen side effects and a progressive loss of credibility for public health authorities. In the waning days of the flu season, the incoming Secretary of what was then the Department of Health, Education and Welfare, Joseph Califano, asked Richard Neustadt and Harvey Fineberg to examine what happened and to extract lessons to help cope with similar situations in the future.