The housing crisis confronts two of North America's contemporary urban challenges: affordability and the need to curtail urban sprawl through densification of existing communities. Advancing a novel formula labelled BAAKFIL, this book introduces a new way of thinking about affordability and revitalization of mature neighbourhoods and communities. Beginning with an exploration of the monoculture of homogenous, average quality suburban housing stock in North America, subsequent chapters explore the serious issue of land cost; infill, zoning and Nimbyism in the context of the mass housing industry. Then, bridging the gap between theory and practice, the author introduces a theoretical design approach (BAAKFIL) as a practical formula for adding affordable residential units in established single family neighbourhoods while respecting their defining features. The final chapters evaluate the efficacy of BAAKFIL as a conceptual model by exploring various 'test bed' sites where the framework is applied. This book will be a valuable resource for practicing architects in the housing domain, as well as for planners working in municipalities. It will also appeal to advanced undergraduate and postgraduate students of urban design and architecture.