The main part of this work covers six historical figures who pioneered in their thinking and writing about the environment: Mary Austin, Florence Merriam Bailey, Rosalie Edge, Marjory Stoneman Douglas, Helen Nearing, and Rachel Carson. A later chapter gives portraits of six post-World War II conservationists: Faith McNulty, Ann Zwinger, Sue Hubbell, Anne LaBastille, Mollie Beattie, and Terry Tempest Williams. The work covers a broad range of conservationist concerns, including preservation of deserts and old growth forests, wildlife protection, wetlands maintenance, self-sufficient sustainable ways of producing food, and pollution control. A conclusion examines where conservationists have picked up after Rachel Carson's Silent Spring (1962) and gives conservation ideas for our time. An appendix lists the published writings of the twelve conservationists.