This article is adapted from Alan Durning's new book, "Unlocking Home: Three Keys to Affordable Communities"; Sightline Institute."[A] good hotel room of 150 square feet -- dry space, perhaps with a bath or a room sink, cold and sometimes hot water, enough electric service to run a [light] bulb and a television, central heat, and access to telephones and other services -- constitutes a living unit mechanically more luxuriant than those lived in by a third to a half of the population of the earth." Paul Groth in "Living Downtown: The History of Residential Hotels in the United States."Most Americans live in houses or apartments that they own or rent. But a century ago, other less expensive choices were just as common: renting space in families' homes, for example, or living in residential hotels, which once ranged from live-in palace hotels for the business elite to bunkhouses for day laborers. Working-class rooming houses, with small private bedrooms and shared bathrooms down the hall, were particularly numerous, forming the foundation of affordable housing in North American cities. Misguided laws and regulations almost wiped out these other kinds of housing, with disastrous consequences, but now there's a chance for them to come back, helping those who are young, single, or on the lower rungs of our increasingly unequal society.