TY - BOOK N2 - Brief biographies of eight American pioneers in conservation and ecology: Henry David Thoreau, George Perkins Marsh, Frederick Law Olmsted, John Muir, Gifford Pinchot, George Norris, Aldo Leopold, and Rachel Carson. AB - Brief biographies of eight American pioneers in conservation and ecology: Henry David Thoreau, George Perkins Marsh, Frederick Law Olmsted, John Muir, Gifford Pinchot, George Norris, Aldo Leopold, and Rachel Carson. T1 - Guardians of tomorrow;pioneers in ecology DA - [1971] CY - New York, AU - Hirsch, S. Carl. ET - [1st ed.] CN - QH541.14 .H57 1971 CN - QH541.14 PB - Viking Press PP - New York, PY - [1971] ID - 54479 KW - Ecology KW - Conservation of natural resources KW - Naturalists. KW - Conservation of natural resources. KW - Ecology. SN - 0670356468 TI - Guardians of tomorrow;pioneers in ecology ER -