The medical profession has been closely associated with the rapid industrial development of the United States during the last two decades—more closely than most physicians realize. Many great industries have awakened to the economic value of preserving their human machines. Formerly the human machine was used to the utmost, and, when broken, was thrown on the scrap heap; today, at least five states, as well as the federal government, have passed rehabilitation laws, with a view to salvaging the disabled employee and replacing him in industry as a productive unit of society. Forty-two states have passed employees' compensation laws; many of them are still inadequate, but all are for the purpose of paying the just claims of men disabled by their work. Thus the industrial world is filled with great medico-economic and medicolegal problems, whose solution depends primarily on the assistance of the leaders in the medical profession.