The minimum age of the women offenders studied was 16 years old, and there was no upper age limit. The women studied were 102 consecutive cases committed to the State Reformatory for Women in Bedford Hills between September 1, 1916 and August 9, 1917; 88 women committed to the State Prison for Women in Auburn, N.Y. between February 4, 1915 and June 27, 1917; 76 women received at the Magdalen Home in New York City between September 29, 1916 and June 15, 1917; 110 women committed consecutively to the New York County Penitentiary between January 12, 1916 and May 14, 1917; 109 women from the New York City workhouse; and 102 women under probation from the Women's Night Court of Manhattan and the Bronx from March 1916 through July 1917. Data obtained covered psychological characteristics, criminal histories, birthplace, and race. Other data collected pertained to early home conditions and family status, educational background, occupational history and economic efficiency, and mental capacity. Data indicate that female criminality is related primarily to poor economic background, limited educational opportunity, having to work at an early age, meager industrial training, and low intelligence. 225 tables, 76-item bibliography, and a subject index