Politics and government 1,575,428 Philosophy 316,942 Political science 290,074 Periodicals 284,890 Political aspects 120,154 Popular music 119,871 Piano music 107,408 Prevention 96,345 Population 88,330 Psychological aspects 88,196 Poetry 84,551 Psychology 84,207 Political activity 75,859 Presidents 68,325 PRO Gotham Book Mart (former owner) (Gotham Book Mart Collection copy) 59,533 Photography, Artistic 57,606 Pollution 53,369 Pictorial works 50,395 Public opinion 49,965 Politique et gouvernement 49,685 Public health 49,460 POLITICAL SCIENCE 48,796 Planning 48,730 Painting 47,282 Physics 46,836 Political parties 45,882 Prices 45,347 Politicians 44,575 Police 41,518 Peace 40,214 Political and social views 38,644 Painters 38,532 Physicians 37,800 Printing 37,634 Photography 37,498 Penn dissertations 37,109 Public lands 36,322 Plants 34,585 Private collections 32,550 Public welfare 31,657 Poverty 31,181 Political participation 30,606 Poor 30,278 Paleontology 30,143 Personnel management 29,033 Physiology 29,029 Publishers and publishing 27,786 Petroleum industry and trade 27,729 Philosophie 26,598 Popular culture 26,565 Psychoanalysis 25,556 Public administration 24,999 Postal service 24,993 Prisons 24,101 People with disabilities 23,935 Power resources 23,819 Patients 22,531 Painting, Chinese 22,372 Public buildings 21,939 Pensions 21,938 Physiological effect 21,847 Petroleum 21,121 Political corruption 20,910 Public Policy 20,854 Philosophers 20,347 Protection 19,975 Philosophy, Modern 19,532 Prisoners 19,337 Psychotherapy 19,023 Political prisoners 19,001 Prayer 18,940 Peasants 18,767 Portraits 18,625 Painting, Modern 18,503 Piano, Musique de 18,362 Political culture 17,930 Politics, Practical 17,739 Psychiatry 17,551 Penn theses 17,263 Production and direction 16,968 Palestinian Arabs 16,752 Philosophy, Chinese 16,653 Public schools 16,218 Psalms (Music) 15,794 PSYCHOLOGY 15,610 Public Health 15,602 Piano music, Arranged 15,290 Public works 15,269 Public contracts 15,035 Power (Social sciences) 14,801 Phonology 14,578 Politique gouvernementale 14,554 Press 14,524 Philosophy, Ancient 14,423 Physical geography 14,325 Piano trios 14,018 Personal narratives 13,755 PHILOSOPHY 13,656 Painting, Italian 13,479 Poetics 13,412