The United States government conducted four negative income tax (NIT) experiments between 1968 and 1980. NIT is a form of basic income guarantee that was popular in the 1960s and 1970s. Some of the political background to the NIT in Office of Economic Opportunity (OEO) has not been commonly known. Because the money for the experiment was to be taken from the Community Action Demonstration Program, there was a substantial sum of tens of millions of dollars available. The chapter reviews the results of the experiments with respect to the labor supply, which was the central issue driving the design of all experiments. It examines the non-labor supply outcomes that have largely been ignored and that covered a territory that was ahead of its time in many ways. The chapter provides the findings of the experiments, and argues that the NIT experiments set a standard in seeking reliable information. The policy analysts at OEO were not public relations types but academically oriented social scientists.