It is what architects have in common rather than what separates them that is at the root of their legendary quarrels. Architectural identities are shaped by imitating preferred architectural forms and by imitating the identities of their makers. But although imitation (mimesis) is both essential and useful, it has another side, one that makes it a cause for rivalry, something René Girard has called "mimetic rivalry". Mimetic rivalry occurs because of competition for what is commonly shared, for what is commonly desired. Architects usually explain their rivalry as the result of personal and ideological differences, unaware that the desire to imitate a master becomes the desire to obtain the same forms, the same status. For the first time in architectural literature, this book introduces and explains the idea of mimetic rivalry that many architects experience without understanding its source.