The book investigates how much embodied and consumed carbon is used in each typology and how it affects density and open space from the viewpoint of sustainability, carbon emissions, and carbon sequestration. The study determines which building typology is the most sustainable on a comparative basis. Nine prototypical buildings were designed--Megatall, Supertall, High-Rise, Mid-Rise, Low-rise, Courtyard, Three-Flat, Urban Single-Family, and Suburban Single-Family -- set within nine prototypical communities. The study designates an archetypal residential community of 2,000 units with an average unit size of 150 sm as a reasonable and representative cross section of different housing typologies.