than new ones, and that most economic innovation happens in old buildings (Brand, 1994, p. 84). Real estate markets, which tend to be volatile, can kill communities and buildings. Both boom and bust markets can be damaging. Bust markets obviously devalue and bankrupt communities. In boom markets, land values in urban downtowns overwhelm the value of existing buildings, which become disposable. They encourage high-rise development (to get the most rent per hectare), while property tax assessments penalize homeowners for making improvements. Similarly, in the suburbs, the treatment of homes as investments rather than habitat creates housing monocultures that are often enforced by rigid prohibitions on the kinds of renovation allowed. Absentee owner-renter relationships are usually deadly to a healthy builtenvironment. The owners have little stake in proper maintenance, and an economic incentive to minimize it, and the renterswho want to improve the buildinghave no equity stake in doing so. Mortgages once had something of a good side, in that they made outright ownership possible for many people. Their bad side, however, is that they represent a constant drain of resources, with two out of every three dollars spent on the purchase of a building going to pay interest. Christopher Alexander points out that these are resources that should rightly be devoted to continuing maintenancewhich is absolutely critical to resource conservation (Brand, 1994, p. 86). Whats more, mortgages have lost much of their good side and been submerged by a more sinister role in the modern debt-based Casino Economy.