Any of various professional activities or methods concerned with providing social services (such as investigatory and treatment services or material aid) to disadvantaged, distressed, or vulnerable persons or groups. The field originated in the charity organizations in Europe and the U.S. in the late 19th century. The training of volunteer workers by these organizations led directly to the founding of the first schools of social work and indirectly to increased government responsibility for the welfare of the disadvantaged. Social service providers may serve the needs of children and families, the poor or homeless, immigrants, veterans, the mentally ill, the handicapped, victims of rape or domestic violence, and persons dependent on alcohol or drugs. See alsowelfare.