In our day, when the question of how and to what extent and by whom economic activity should be regulated is wide open as between legislative, executive, and judicial branches of government and a galaxy of highly developed private interest groups, the traditional Progressive idea of the just and all-wise commission as final arbiter seems dated. Mr. Ritchie shows that it was an idea to which James M. Landis clung enthusiastically, largely as a result of his experience on the Securities and Exchange Commission, until his later experience as Chairman of the Civil Aeronautics Board and finally as a lawyer representing one of the parties at interest before the Board. From the mounting evidence that a successful regulatory function grows, if at all, out of an appreciation of the economic realities of the particular activity being regulated, may yet come a national policy to which all may repair. Piling up such evidence is one of the most valuable public services the historian can render.