The contribution which a bibliography is able to make to the study of any subject lies probably as much in the viewpoint it incorporates and the method of presentation it uses as in the references it presents. The scheme of classification here employed may lay claim to offering a rather new approach to the study of the city. It will probably have to be modified as new material is discovered and as the sociologists themselves continue to make their own distinctive contributions. It ought to offer an index to the aspects of the city that promise most in the way of results from research. At the same time it may be of assistance in organizing and funding the rapidly increasing body of knowledge concerning the sociology of the city. A TENTATIVE SCHEME FOR THE CLASSIFICATION OF THE LITERATURE OF THE SOCIOLOGY OF THE CITY[74] I. The City Defined 1. Geographically: by site, situation, topography, density 2. Historically: by political status, title, law 3. Statistically: by census 4. As an economic unit 5. Sociologically II. The Natural History of the City 1. Ancient cities: Asia, Egypt, Greece, Rome 2. The medieval city 3. The modern city III. Types of Cities 1. Historical types 2. Location types: sea coast, inland, river, lake 3. Site types: plain, valley, mountain, hill, harbor, island 4. Functional types: capital, railroad, port, commercial, industrial, resort, cultural 5. The town, the city, and the metropolis 6. Structural types: the natural city and the planned city IV. The City and Its Hinterland 1. The trade area 2. The commuting area: the metropolitan area 3. The administrative city 4. The city and its satellites 5. The city and its cultural periphery 6. The city and world economy V. The Ecological Organization of the City 1. Natural areas 2. The neighborhood 3. The local community 4. Zones and zoning 5. The city plan VI. The City as a Physical Mechanism 1. Public utilities: water, gas, electricity 2. Means of communication: telephone, mails, telegraph, street-car, busses, automobile 3. Streets and sewers 4. Public safety and welfare: fire, police, health departments, social agencies 5. Schools, theaters, museums, parks, churches, settlements 6. Recreation 7. City government: the city manager, the boss 8. Food supply, stores (department and chain stores) 9. Steel construction: the skyscraper 10. Housing and land values VII. The Growth of the City 1. Expansion 2. Allocation and distribution of population: “city-building” 3. Population statistics: natural growth and migration 4. Mobility and metabolism in city life 5. Social organization and disorganization and city growth VIII. Eugenics of the City