For the Gulf region, housing markets and policy design is a critical topic, because housing is what creates and defines cities, and affordable housing, as we will show, is what makes successful and scalable cities. Indeed, housing is the spatial expression of a society’s values and morality, and of its commitment to an inclusive society. In the Gulf region, characterized by rapid urbanization and astonishing transformation over the last two decades, housing is absolutely urgent as a national priority. Affordable Housing Is Essential to the Gulf Region Every nation in the world either has already urbanized or is urbanizing rapidly – and as people urbanize, housing moves from being a physical good to a money good. Physical goods are homes that people can make with their own labor and indigenous or found materials and occupy at zero cash cost. Money goods are homes where the occupant pays money for use of the land, either by buying the land or by renting it. Once housing becomes a money good – that is, something people have to pay for rather than manufacture themselves – its delivery requires finance, both for the eventual consumer/occupant/homeowner and for the development process. As nations urbanize, cities go progressively more vertical.3 The average height of the built environment continually rises to accommodate ever more people living and working in the same land footprint. As that happens, the structures in which people live and work become progressively more technological, sophisticated, and consequently large. No longer is housing four simple walls and a sloping roof; instead it is the nexus of a host of physical systems – water, sewer, electricity, HVAC, telecommunications, broadband – of increasing complexity and systemic intelligence. The complexity inherent in the design and construction of these buildings makes them progressively larger, with a larger physical footprint of required land (even as that land is being more efficiently and intensively used), so it is the trend globally that as nations and cities become wealthier, people live in buildings with more and more neighbors (abutting them in walls, floor, or ceiling), higher and higher in the air.