||The purpose of this dissertation is to investigate the meaning of the concept of Type in the field of architectural theory. Even though the use of the term type by architectural theorists is a relatively recent phenomenon, which can be traced back to Quatremère de Quincy in the early nineteenth century, the idea of Type, as opposed to the explicit use of this term by theorists, has pervaded much of architectural theory ever since Vitruvius. In fact, many theorists have been concerned with issues which convey a notion of Type, like the origins of architectural form, the systematization of architectural knowledge and the understanding of the process of creativity. A basic premise of this work is that to understand the true significance of the idea of Type in architecture, it is necessary to overcome certain traditional views that have associated Type with the work of specific authors at a given time like, for example, Quatremère de Quincy and Semper in the nineteenth century, or Rossi in the twentieth. Only a comprehensive study of the most relevant ideas formulated in the field of architectural theory -beginning with Vitruvius and finishing with contemporary design methodologists- can reveal the essential meaning, or meanings, of Type. This work attempts to provide such a comprehensive study. To derive the fundamental meanings of the concept of Type from the body of the architectural tradition, it has been necessary to proceed, simultaneously, along two different lines: one diachronic, the other synchronic. From a diachronic point of view, the aim has been to trace the evolution of the theories of Type from one author to another, for example from Laugier to Quatremère de Quincy. From a synchronic point of view, the goal has been to disclose the common ideas that lie behind theories formulated at different times, for instance, between Vitruvius' theory of the origins of architectural form and the artistic theory developed after the advent of Gestalt psychology. In recent times, the term type has been used by architectural writers as synonymous with typology. Unfortunately, establishing this identity between type and typology has served to undermine some of the essential meanings conveyed by Type. In the overall context of the architectural tradition, the idea of Type has much deeper implications than those that are confined to the classification and study of building forms. Type embraces transcendental issues of aesthetic, epistemological and metaphysical character; issues that have to do with the most generic problem of Form. Certainly, the essential meaning of Type is intimately related with the more transcendental problem of Form. To explore the relation between the idea of Type and the historical evolution of architectural form, has also been the purpose of this research. As this work attempts to show, the variety of meanings that Type has adopted through history are inseparably connected to the evolution undergone by architectural form. For that reason, this work, although primarily a study of the concept of Type, it is, at the same time, an investigation on the nature of architectural form.