I have described four distinctively different types of neighborhoods.
Assuming that the findings of the Baltimore studies are generally valid
(they need, of course, to be tested in other places), my argument, the
central thesis of this book, is that all cities, in order to satisfy significant
groups in the population, must offer all four types of neighborhoods. The
absence of any of the types would deny housing choices and so diminish
the overall quality of life. Not only must cities offer all four types of neigh-
borhoods, but they must offer good examples of each, which means that
each type must possess, to the highest degree possible, the qualities that I
have identified.

Some of these qualities refer to physical attributes of the setting, while
others refer to the social relationship between neighbors. A plan for good
neighborhoods must address both sets of qualities.

Physical qualities are concerned with the form, appearance, and sanc-
tioned use of neighborhood structures and spaces (for example, a quiet, all-
residential environment, a dense pattern of development, and organization
around a strong center), and are addressed through familiar planning de-
vices such as land use regulations, street design standards, site planning
guidelines, density limits, height restrictions, and locational criteria for pub-
lic buildings. But while concern for the physical qualities of a neighbor-
hood is generally accepted as the basis for public policy, concern for the
social behavior of its residents (for example, their friendliness, sophistica-
tion, and civic involvement) is not. The prevalent belief in the United States
is that it is not appropriate for a public agency to establish behavioral stan-
dards for prospective residents--which is to say, to plan who will live in a
particular neighborhood and who will not.

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