Ten specialists have collaborated in the preparation of this survey of the settlement possibilities of the world's remaining empty lands. Though working independently, they all reach the conclusion that only small-scale colonization of these areas is practicable and that this will afford no material relief to the countries now feeling the pressure of population upon their means of subsistence. Where the population is thin there are meagre opportunities for newcomers because of unfavorable climate, lack of transportation and educational facilities, and remoteness in space or time from the world's markets. The text is profusely illustrated with maps and charts. Current discussion of colonies for the "have-not" countries gives the work a timely interest. It was prepared for the American Coördinating Committee for International Studies.