History 6,340 Politics and government 1,921 Roads 845 Education 711 Geology 704 African Americans 700 Description and travel 634 Law and legislation 632 Railroads 622 Social life and customs 619 Law 618 Housing 610 Indians of North America 601 Finance 574 Periodicals 572 City planning 454 Manners and customs 431 Antiquities 428 Women 423 Social conditions 414 Biography 405 Public lands 394 Universities and colleges 392 Statistics 390 Regimental histories 375 Economic conditions 371 Maps 368 Frontier and pioneer life 366 Soils 358 Agriculture 353 Soil surveys 346 Law reports, digests, etc 344 Slavery 339 Canals 320 Taxation 320 Art 315 Wages 310 Mortgage banks 309 Public buildings 299 Banks and banking 286 Environmental aspects 281 Buildings, structures, etc 274 Population 274 Church history 267 Real property 265 Travel 255 Buildings 254 Water-supply 251 Jews 240 Political science 234 Groundwater 231 Societies, etc 231 Water quality 224 Mortgage loans 220 Public schools 214 Labor unions 212 Curricula 211 Pollution 211 Harbors 207 Geology, Stratigraphic 204 Study and teaching 204 Industries 199 Floods 197 Employment 195 Historic buildings 195 Baptists 189 Architecture 186 Elections 186 Civil procedure 184 Exhibitions 183 Design and construction 182 Finance, Public 180 Sources 180 Antislavery movements 177 Paleontology 172 Boundaries 169 Catalogs 166 Murder 165 Bridges 162 Courts 162 History, Local 162 Judges 158 Soldiers 158 Speeches, addresses, etc., American 158 Bibliography 157 Land grants 157 Lighting, Architectural and decorative 157 Mounds 157 Cities and towns 156 Employees 156 Architecture, Domestic 155 Cooking, American 155 Economic history 154 Coal mines and mining 153 Race relations 153 Libraries 152 Water 152 Botany 151 Forms (Law) 150 Mines and mineral resources 150