Columbia subject headings:
Industrial relations--United States--History.
United States--Social conditions--1865-1918.
United States--Social conditions--To 1865.
Working class--United States--History.
Harvard subject headings:
Industrial relations--United States--History
United States--Social conditions--1865-1918.
United States--Social conditions--To 1865.
Working class--United States--History
Princeton subject headings: