“American foursquare” refers to a house type that is little recognized in traditional architectural history sources yet is visible in virtually any urban neighborhood developed during the period 1900–40. Despite its lack of official approval, this hardy survivor was far and away the dwelling of choice for generations of people with modest means constructing or purchasing homes. The design was eminently practical: it was spacious, it was passably attractive, and it was cheap. Variously called “Builder’s Houses,” “American Basic,” “Square Houses,” “Box Houses,” “double-deckers,” “double cubes,” “American Farm Houses” (something of a misnomer, since the vast majority of these homes were built in cities and suburbs), or, because of their sheer numbers across the land, “National Houses,” the houses themselves remain clearly boxlike in their design. The foursquare design is often not truly square. In its rectilinear proportions, lowhipped roof, square plan, and simple facades, the foursquare...