Developments toward residential Open Building are widespread and accelerating. They accompany change: in environmental structure, in production and construction methods, in the market for services and products, in product technology, and in the demand for suitable housing. However, unlike many new products or methods, Open Building was not invented. It has not developed in a unified fashion. Nor has it been aggressively marketed or promoted by multinational corporations, governments or associations. Rather, OB has emerged gradually in response to evolving social, political and market forces, to prevailing conditions and trends in residential construction and manufacturing, and to many other factors that demand more effective and responsive practices.