Concerned first with the definition of conservation and its problems, and then with specific actions by the Department of the Interior in response to these problems, this 1966 yearbook provides highlights of work done by the 26 bureaus, offices, and/or administrations within the Department. Coverage is broad, relating to many aspects of conservation in the United States in a descriptive, non-technical style. Numerous colored and black and white pictures, graphics, and accompanying narration serve to elaborate the theme of the endless task of restoring the balance of nature, man, and his institutions. Four special color essays are included depicting the ravages of man on the land, endangered wildlife, beauty of the National Parks, and the rising tide of education. (BL)