Study of the development of residential building typologies in Philadelphia, Pennsylvania, USA, the so-called city of homes because of the predominance of row-houses. Contents: meeting the vernacular; the role of carpenters; modernity of row-houses; typological classification; influence of architectural styles; urban reform (in the 1930s) and introduction of new building typologies; recent development of the family unit house, against the developers of the the so-called Pop approach of the 1960s under the leadership of Venturi, Rauch & Scott Brown.