The evolution has been a gradual growth arising out of realized needs, rather than a logical development based on general principles; and as politicians and legislators seldom take a wide outlook, or consider a specific proposal in relation to what is already being done, and to what is the desired goal, the English experience is especially instructive. _Town-living and Health Problems_ Public health work became an urgent necessity when men began to huddle in towns; and with the industrial revolution of the eighteenth and early nineteenth centuries the need for remedial action became acute. It is hard to realize that in the days of our grandfathers, the home was in most instances the unit of industry; and that in the eighteenth century communications between districts and towns were not more advanced than those of the ancient Egyptians. When, however, vast urban aggregations of population multiplied, travelling facilities rapidly increased, and the results of crowding, of contaminated water supplies, of intensive and widespread infection, were seen in devastating endemic and epidemic diseases. Poverty, squalor, dirt, and their consequences, were rampant in the towns, where underpaid work-people were exploited by masters, whose self-centred outlook had some share of justification in the political economy doctrines of the time, which regarded any interference with “freedom of contract” as useless or even pernicious. What is public health work? It is best defined by stating its object, which is to secure the maximum attainable health of every member of the community, so far as this can be secured by the authorities, local, state, or federal, concerned in any part of government, acting in coöperation with all voluntary agencies whose work conduces to the same end. The connotation of public health becomes wider year by year. It embraces physiological as well as pathological life; being as much concerned with improving the standard of health of each person as with the prevention and cure of disease. Hence the importance of the “concentration on the mother and her child” (John Burns), to secure for them by all practicable means the conditions of complete health, which during the last twelve years has been a vital part of our public health work, and which is now being made to include not only all hygienic and medical help that may be needed, but also such domestic aid as may enable the mother to bring her children into the world and to rear them under advantageous conditions. _Scope of Constructive Health Work_