Library classification schemes 71 Decimal Classification 63 History 59 Science 43 Politics and government 38 Biotechnology 33 Molecular Biology and Molecular Genetics, (Discontinued March 2000, Reinstated and Revised June 2002) 33 Biotechnology (General), (Revised June 2002) 29 Plant Breeding and Genetics 28 Philosophy 25 LAW / International 21 Law and legislation 21 Pure sciences 21 Classification 20 Dissertations, Academic (Ph.D) 20 International law 19 DDC 18 Democracy 18 Deway decimal classification 18 Intellectual property 18 Literature 18 Agricultural Economics 16 Human rights 16 Social conditions 16 History and criticism 15 Plants 15 Soil Water Management (Irrigation and Drainage), (Revised June 2002) 15 Dewey Decimal Classification 14 Library Science 14 Mathematics 14