Politics and government 1,575,988 Philosophy 317,139 Political science 290,110 Periodicals 284,898 Political aspects 120,219 Popular music 119,885 Piano music 107,438 Prevention 96,362 Population 88,438 Psychological aspects 88,234 Poetry 84,569 Psychology 84,236 Political activity 75,907 Presidents 68,346 PRO Gotham Book Mart (former owner) (Gotham Book Mart Collection copy) 59,533 Photography, Artistic 57,648 Pollution 53,372 Pictorial works 50,379 Politique et gouvernement 49,984 Public opinion 49,980 Public health 49,473 POLITICAL SCIENCE 48,821 Planning 48,737 Painting 47,326 Physics 46,839 Political parties 45,908 Prices 45,350 Politicians 44,590 Police 41,537 Peace 40,223 Political and social views 38,663 Painters 38,573 Physicians 37,812 Printing 37,650 Photography 37,523 Penn dissertations 37,109 Public lands 36,322 Plants 34,596 Private collections 32,574 Public welfare 31,662 Poverty 31,196 Political participation 30,622 Poor 30,281 Paleontology 30,144 Personnel management 29,041 Physiology 29,033 Publishers and publishing 27,795 Petroleum industry and trade 27,737 Philosophie 26,754 Popular culture 26,574 Psychoanalysis 25,564 Public administration 25,010 Postal service 24,997 Prisons 24,107 People with disabilities 23,942 Power resources 23,820 Patients 22,538 Painting, Chinese 22,441 Pensions 21,940 Public buildings 21,940 Physiological effect 21,849 Petroleum 21,125 Political corruption 20,920 Public Policy 20,870 Philosophers 20,369 Protection 19,996 Philosophy, Modern 19,537 Prisoners 19,342 Psychotherapy 19,026 Political prisoners 19,004 Prayer 18,940 Peasants 18,785 Portraits 18,623 Painting, Modern 18,506 Piano, Musique de 18,407 Political culture 17,934 Politics, Practical 17,743 Psychiatry 17,556 Penn theses 17,263 Production and direction 16,974 Palestinian Arabs 16,764 Philosophy, Chinese 16,722 Public schools 16,221 Psalms (Music) 15,796 PSYCHOLOGY 15,625 Public Health 15,608 Piano music, Arranged 15,293 Public works 15,270 Public contracts 15,038 Power (Social sciences) 14,814 Politique gouvernementale 14,647 Phonology 14,603 Press 14,529 Philosophy, Ancient 14,428 Physical geography 14,334 Piano trios 14,019 Personal narratives 13,755 PHILOSOPHY 13,670 Painting, Italian 13,480 Poetics 13,425