National wilderness preservation act. : Hearings before the Committee on Interior and Insular Affairs, United States Senate, Eighty-fifth Congress, first session, on S. 1176, a bill to establish on public lands of the United States a national wilderness preservation system for the permanent good of the whole people, to provide for the protection and administration of the areas within this system by the existing Federal agencies and for the gathering and dissemination of information to increase the knowledge and appreciation of wilderness for its appropriate use and enjoyment by the people, to establish a wilderness preservation council, and for other purposes. June 19 and 20, 1957.