Throughout the nineteenth and twentieth-centuries a growing number of papers on human sexuality have been read at learned conferences. Many of these papers were psychological or statistical in nature and often suffered from a severe lack of hard empirical data. Perhaps the first really empirical paper was first read by Dr William H. Masters in April 1959 at a two-day "Conference of the Vagina" held in New York under the auspices of the New York Academy of Sciences. For several prior years Dr Masters and his colleagues had been studying how the human body actually responded to effective sexual stimulation. Earlier work had been carried out by other scientists: Dr Masters was not the first, but his work was the most detailed, most broadly based, and the most influential in the field of empirical laboratory evaluation of human sexual response.