A few small surveys into sexual behaviour were carried out in the nineteenth century; but perhaps the first of any account was that carried out by P. S. Achilles in 1923. As a psychologist he organised a group-administered questionnaire study of 1449 males and 483 females, all of the subjects from the New York City area. The study was mainly concerned with the effectiveness of certain social hygiene literature in disseminating information about venereal disease, but a number of the questions related to the sexual activities of the subjects. The size of the group is larger than most for that period, but was not broken up into homogeneous groups for analyses.