For more than seven decades, the American government has acted to provide housing for the poor. In America's Trillion-Dollar Housing Mistake, Howard Husock explains how, as with so many anti-poverty efforts, low-income housing programs have harmed those they were meant to help while causing grave collateral damage to cities and their citizens. Public housing projects, Mr. Husock writes, are only the best-known housing policy mistakes. His book explains how a long list of lesser-known efforts including housing vouchers, community development corporations, the low-income housing tax credit, and...