This document provides an introduction to a course on the history and theory of architecture. It discusses the relationship between history, theory, and design. It then provides a brief overview of the evolution of architectural styles throughout history. Finally, it discusses some key concepts in architectural theory, including how theory has developed through writing, and how the internet may further architectural discourse. The architect Vitruvius defined architecture as incorporating utility, firmness, and delight. Architecture is the design of buildings and spaces to meet human needs using technology and science with aesthetic qualities.