Duplexes were popular in the post-war America of the 1950s, and today the twin-house concept may be ready for an encore for many of the same reasons that drove its original rise into fashion. Suited for both urban and suburban environments, the typology’s shared party wall allows for higher lot density (on a single foundation pour, no less) making housing more affordable. Some owners opt to live in one half and rent out the other to supplement their mortgage payments, while others may reserve the extra unit so that aging parents can live next door. At the same time, it’s a building form that allows the luxury of private yard space and separate outdoor entries, as illustrated in the six examples we show here.