• 4 Videos, Slides, Films

• 2 History
• 1 Carson, Rachel, 1907-1964
• 1 Civilian Conservation Corps (U.S.)
• 1 Conservation of natural resources
• 1 Conservationists
• 1 Depressions
• 1 Droughts
• 1 Dust Bowl Era, 1931-1939
• 1 Dust storms
• 1 Economic conditions
• 1 Edison, Thomas A. (Thomas Alva), 1847-1931
• 1 Environmental aspects
• 1 Environmentalists
• 1 Forest conservation
• 1 Horse racing
• 1 Inventors
• 1 Leopold, Nathan Freudenthal, 1904-1971
• 1 Loeb, Richard A., 1905-1936
• 1 Murder
• 1 Murderers
• 1 Naturalists
• 1 Nineteen thirties
• 1 Pesticides
• 1 Pollard, Red, 1909-1981
• 1 Public service employment

• 3 Public Broadcasting Service (U.S.)
• 2 42nd Parallel Films
• 2 American Experience Films
• 2 Platt, Oliver
• 2 Uz, Rafael de la
• 1 Blumer, Ronald H.
• 1 Desert Penguin Pictures (Firm)
• 1 Gazit, Chana
• 1 Gitelman, Lisa
• 1 Halpern, Nathan, 1978-
• 1 Hovde, Ellen
• 1 Insignia Films
• 1 Ives, Stephen
• 1 Kusiak, John
• 1 Livingston, Peter R.
• 1 Lytle, Mark H.
• 1 Meyer, Muffie
• 1 Morgenstern, Eve
• 1 Murphy, Michael, 1938-
• 1 Myhrvold, Nathan
• 1 O'Connell, Cathleen
• 1 O'Donnell, George (Film editor)
• 1 Parker, Mary-Louise

• 4 English

• 3 United States
• 1 Chicago
• 1 Great Plains
• 1 Hoover Dam (Ariz. and Nev.)
• 1 Illinois

Limit year range