Politics and government 1,577,522 Philosophy 317,494 Political science 290,225 Periodicals 284,996 Political aspects 120,577 Popular music 120,462 Piano music 107,594 Prevention 96,525 Population 89,218 Psychological aspects 88,423 Poetry 84,753 Psychology 84,355 Political activity 76,042 Presidents 68,447 PRO Gotham Book Mart (former owner) (Gotham Book Mart Collection copy) 59,533 Photography, Artistic 57,811 Pollution 53,399 Politique et gouvernement 51,274 Pictorial works 50,418 Prices 50,231 Public opinion 50,030 Public health 49,535 Planning 48,780 POLITICAL SCIENCE 48,767 Painting 47,354 Physics 46,870 Political parties 45,951 Politicians 44,688 Police 41,618 Peace 40,228 Political and social views 38,717 Painters 38,587 Physicians 37,835 Printing 37,667 Photography 37,545 Penn dissertations 37,284 Public lands 36,325 Plants 34,617 Private collections 32,558 Poverty 32,366 Public welfare 31,684 Political participation 30,667 Poor 30,302 Paleontology 30,153 Personnel management 29,066 Physiology 29,051 Petroleum industry and trade 28,516 Publishers and publishing 27,835 Philosophie 26,861 Popular culture 26,612 Psychoanalysis 25,562 Public administration 25,060 Postal service 25,003 Prisons 24,137 People with disabilities 24,038 Power resources 23,852 Patients 22,603 Painting, Chinese 22,451 Pensions 22,424 Public buildings 21,948 Physiological effect 21,855 Petroleum 21,136 Political corruption 20,973 Public Policy 20,867 Philosophers 20,411 Protection 20,098 Philosophy, Modern 19,573 Prisoners 19,377 Psychotherapy 19,107 Political prisoners 19,034 Prayer 18,995 Peasants 18,814 Portraits 18,646 Painting, Modern 18,569 Piano, Musique de 18,548 Political culture 17,962 Politics, Practical 17,712 Psychiatry 17,569 Penn theses 17,263 Production and direction 17,051 Palestinian Arabs 16,799 Philosophy, Chinese 16,732 Public schools 16,228 Psalms (Music) 15,804 Public Health 15,647 PSYCHOLOGY 15,609 Piano music, Arranged 15,319 Public works 15,272 Public contracts 15,047 Politique gouvernementale 15,043 Power (Social sciences) 14,834 Phonology 14,612 Press 14,536 Philosophy, Ancient 14,431 Physical geography 14,342 Piano trios 14,036 Personal narratives 13,731 PHILOSOPHY 13,635 Painting, Italian 13,485 Poetics 13,441