In 1918, the Treasury Department established a Special Narcotic Committee, tasked with reviewing the scope of the drug problem in the United States. The Committee issued its final report, Traffic in Narcotic Drugs, in June of 1919. The product of a year’s worth of work by a committee which included reputable figures in the drug field, the report covered many aspects of the drug problem—but no part of the report drew more attention than the conclusion that the nation’s addict population numbered one million. To understand how that figure was obtained, we need to briefly review some very poor statistical analysis. And that’s part of the story. But the bigger story is that “one million addicts” took on a life of its own, a mythical number that long outlived the federal government’s own interest in its promulgation.