UNDER this title, the American Association for the Advancement of Science has issued a selected list of literature dealing with various aspects of the subject. Almost too late, rather than too soon, the United States is becoming conscious of the significance of the vast subject of conservation. The very word is itself indicative of a more sober outlook. The falsely alluring concept of limitlessness which in the last century tempted Americans to embark on a policy of exploitation concurrently with expansion has gone ; in certain spheres retreat has followed expansion and many rueful surveys are being made of what has been left, with sound suggestions as to how it may best be used for the future. America wants to reverse the processes by which “man has violated basic arrangements in a manner which Nature will not tolerate”. The literature covers a wide range of subjects, including land use, which in this continent is especially bound up with the subject of soil erosion ; forestry and afforestation, important not merely because “almost every one of the forty-eight states is headed towards forest bankruptcy in timber” but also because deforestation has had a terrible sequel in floods, soil wastage and silted rivers. Lists of books on "Oil and Gas Conservation" and “Saving Our minerals” indicate that the future shortage of these vital products has passed from the realm of prophecy to that of serious and calculable prediction. The inclusion of a section on the conservation of wild life serves to show how important is this question, both in and out of the national parks which are of increasing value to the States.