History 25 Education 23 Physics 15 Law 11 Literature & literary studies 11 Universities 10 Literature: history & criticism 9 Politics & government 9 Environmentalist thought & ideology 8 Humanities 8 Science: general issues 8 Social impact of environmental issues 8 Teacher training 8 Teaching skills & techniques 8 The environment 8 Literary studies: general 7 Society & social sciences 7 Dictionaries of biography (Who's Who) 6 Earth sciences, geography, environment, planning 6 Ecological science, the Biosphere 6 History of science 6 Language 6 Educational equipment & technology, computer-aided learning (CAL) 5 Philosophy 5 Study & learning skills: general 5 linguistics 5 Adult education, continuous learning 4 Communication studies 4 Conservation of the environment 4 Economic history 4