What if a patron wants to find books on a certain subject?

Library of Congress Classification System: H

H     Social Sciences (Level 2)

H: Social Sciences (General)

HA: Statistics

HB: Economic theory, Demography

HC: Economic history and conditions

HD: Economic history and conditions

HE: Transportation and communications

HF: Commerce

HG: Finance

HJ: Public Finance

HM: Sociology (General)

HN: Social history and conditions, Social problems, Social reform

HQ: The family, Marriage, Women

HS: Societies - secret, benevolent, etc.

HT: Communities, Classes, Races

HV: Social pathology, Social and public welfare

HX: Socialism, Communism, Anarchism