Cities around the world have adopted social housing as an inalienable aspect of city-making. Understanding it as an ecology within cities will determine its design and success but it needs active government involvement to frame policies and principles. New York’s tryst with social housing, captured in A History of Housing in New York City by noted architect, historian and Professor Emeritus at Columbia University, Richard Plunz, offers an interesting case study for other cities, certainly for Mumbai where nearly half its population is forced to live in slums.