(1838-1914) an American, born in Scotland, who was one of the first conservationists (= people who work to preserve the natural environment). He helped to establish Yosemite National Park and Sequoia National Park in California. Muir Woods National Monument in California and Muir Glacier in Alaska were named after him. His books include The Mountains of California (1894) and Our National Parks (1901). The John Muir Trust was established in 1983 to protect land in Britain.