Shelter has always been a fertile field of investigation for humans and is, in fact, the architectural program that has the longest track record. Dwellings are the quintessential spaces that define personal and family life, and at the same time, the residential fabric is what defines the character and image of the city. The concept of the domestic space is in constant evolution, reflecting new ways of living and proposing new relationships between private and public space. Building on visionary models of the past—from single-family homes to collective housing complexes—architects, designers and urban planners are continuing to experiment in response to the demanding challenges we face now and in the future.