History 26 870 Congresses 13 359 Politics and government 9 318 Periodicals 7 564 Economic conditions 7 215 History and criticism 7 088 Biography 6 308 Education 5 178 English fiction 4 730 Social conditions 4 220 Bibliography 4 169 Fiction 4 075 Description and travel 3 412 Research 3 391 Economic policy 3 368 Study and teaching 3 333 Criticism and interpretation 2 916 Management 2 897 Foreign relations 2 881 Economic aspects 2 874 Social life and customs 2 674 Data processing 2 615 Philosophy 2 577 Agriculture 2 477 Mathematical models 2 476 Accounting 2 415 Science 2 308 Geology 2 293 Finance 2 219 Statistics 2 218