Business: when Landlords Walk Away

THE U.S. is stumbling into a rapidly worsening housing shortage. Soaring costs and shrinking credit have crippled new construction even though vacancy rates have fallen to a 20-year low. Yet in many of the nation's troubled central cities, the most visible housing difficulty is of an entirely different order —a lack not of buildings but of neighborhoods deemed fit to live in, even by the poor. As a consequence, acres of houses and apartment buildings have been abandoned by their owners and tenants to decay.

No one knows exactly how many abandoned dwellings there...