The Salk Vaccine Field Trial was a randomized, placebo‐controlled trial designed to test the efficacy of the Salk killed virus vaccine. Although the trial was not without some problems, both in design and analysis, none was important enough to raise serious questions about the results. Thus, the design of the Field Trial was well adapted to the demanding requirements. The trial owes its success in a large part to substantial public involvement. In designing future, large‐scale, simple trials, we may still be able to benefit from the lessons of the Polio Vaccine Trial.