Wilderness areas Social life and customs 59 Nature conservation 44 Hunting 36 Rural families 36 Self-reliant living 36 Survivalism 36 more ... Description and travel 33 Natural history 32 History 26 Authors, American 20 Environmental aspects 20 Solitude 20 National parks and reserves 18 Philosophy 17 Travel 17 Environmental conditions 16 Management 16 Homes and haunts 15 Trapping 14 Human ecology 13 Nature 12 Conservationists 10 Environmental protection 10 Government policy 9 Adventure and adventurers 8 Effect of human beings on 8 Fishing 8 Philosophy of nature 7 Summer 7 less ...