THE advent and growing use of air transport has done a great deal to alter geographical values. Speed has reduced the importance of distance and thus recast many political, economic and social relationships. In a small pamphlet recently published ("Air Transport and Geography."London : Royal Geographical Society, 1947. Is.), Mr. W. G. V. Balchin refers to many of the aspects of geography that touch on the course and uses of air routes. After referring to the vexed problem of air maps and their projections, he inserts a world map on an oblique zenithal equidistant projection centred on London and its antipodal point ; on this the chief civil routes are shown. These maps show that 94 per cent of the world‘s population, and nearly all the world‘s manufacturing industry, fall in one of these hemispheres, and the central hub is in western Europe with London or Paris the actual centre. The distribution of population, especially - of large urban growths, determines the course of the chief air routes. There are some forty-four world areas each of more than a million inhabitants, of which the largest are in Europe and the Atlantic side of North America and fewest in Africa and in Asia, outside China and Japan. The greatest number are on a great circle track through London and Melbourne. Major flying routes do not cross the Pacific, and contrary to often expressed belief, do not pass through north polar regions. Mr. Balchin goes on to consider other factors influencing the course of air routes.