Thesis (Ph.D.)--Boston University / The concept of "delinquencty area" denotes a social phenomenon. It is generally defined as an area of a city marked by an abnormal delinquency rate as compared with other areas of the city of similar size and population. Such areas are located in zones of transition, and are marked by industrial buildings, waterfronts and railroads, deteriorated buildings, and population of mixed nationalities. In spite of the criticisms of the concept of "delinquency area," it appears to serve a useful purpose. There is a danger that the concept may be used as an oversimplification of the problem of delinquency and crime, because of the extreme complexity of delinquency and crime causation and the inconclusive nature of most statistical data on this subject. Probably the concept of "delinquency area," if refined, would be of increasing use in research. However, it should be noted that delinquency may be of various types. Some of these types may exist in certain areas, and others may breed in other areas. If we wish to find out the dynamic factors that may cause a type or types of delinquent behavior, the concept will provide us with a starting point from which to look for these factors. For example: We may be able to find out the reasons why certain types of delinquency occur in others; or why they occur more often in certain areas than in other areas of the same city. [TRUNCATED]