Nothing could better express the spirit of the old frontier which, more than any other feature in American life, has served to characterize American institutions and American mores. The hobo is, in fact, merely a belated frontiersman, a frontiersman at a time and in a place when the frontier is passing or no longer exists. ROBERT E. PARK CHAPTER X A BIBLIOGRAPHY OF THE URBAN COMMUNITY The task of compiling a bibliography on the city which is to be of use to the sociologist involves many difficulties. The materials are scattered over many fields of investigation ranging all the way from the various branches of the natural and social sciences to the practical arts and crafts. Much of the material is highly technical and abstract, while the rest is popular and full of human interest. If one attempts to survey the whole field he is likely to be led into tempting bypaths which lead far afield and in the end arrive nowhere. Moreover, the bibliographer has neither chart nor compass to guide him in his search, for the sociologist himself is not yet certain of the meaning of the concept “city” and of the relationship of his science to the phenomenon. Specialization has gone so far that no one can hope to become an expert in more than one field in a lifetime. The sanitary engineer, interested in urban sanitation, is mainly concerned with drainage systems, pumps, sewer pipes, and incinerators; but the accountant, the political scientist, and the sociologist are not primarily interested in these matters. At first glance the sociologist might be tempted to pass over such material as lying outside his province, while he would be less likely to pass over materials relating to parks, playgrounds, schools, infant mortality, city-planning, and non-voting, because these institutions and processes have traditionally held the sociologist’s interest. And yet it is within the realm of possibility that such a question as that of the type of sewer pipe that is to be employed in a city drainage system may become one with which the sociologist is as legitimately concerned as the question of city-planning or juvenile delinquency.