"I have sought to establish an analytical method susceptible to quantitative evaluation and capable of collecting the material to be studied under unified criteria. This method, presented as a theory of urban artifacts, stems from the identification of the city itself as an artifact and from its division into individual buildings and dwelling areas."

In the introduction to the first American edition of The Architecture of the City (1981), Rossi writes that certain themes presented in the book led him to the concept of analogy.

"The overlapping of the individual and the collective memory, together with the invention that takes place within the time of the city, has led me to the concept of analogy. Analogy expresses itself through a process of architectural design whose elements are pre-existing and formally defined, but whose true meaning is unforeseen at the beginning and unfolds only at the end of a process."