The real force behind the fifth migration is not the affluent newcomers from the suburbs who "discover" a neighborhood close to the core, but the global migration of immigrants from around the world as well as longer-term residents who are rediscovering the possibilities of inner cities located strategically between the downtown regional core and the suburbs. Today, it is perhaps only in the New York region that one can see the region-wide impact of the fifth migration. The planning challenge of the fifth migration is to implement policies that not only capitalize on and institutionalize present demographic trends but create diverse, livable, and vibrant cities that can sustain themselves long into the future. If there is a single key area in which public policy can guide and encourage the fifth migration, it is surely housing. For a proper housing policy responds to the two major dangers that could defeat the potential of the fifth migration.