Harry H. Laughlin's professional files from the Eugenics Record Office, 1910-1939. These files contain institutional correspondence, memoranda, and reports; general correspondence; correspondence and printed materials related to the eugenical organizations to which Laughlin belonged; working manuscripts; notes; miscellaneous collected printed materials; some photographs; and glass lantern slides which were used for presentations. Laughlin, as one of the leaders in the eugenics movement, was interested in every aspect of genetics, genetics research and the furthering the eugenical cause. The collection reflects Laughlin's very strong interests in the identification of the "socially inadequate," genetically caused diseases, eugenical sterilization, immigration restriction, and the establishment of a common world government. Laughlin was also involved in thoroughbred horse breeding studies, a practical application of genetics.