The book, a documentary history, records a cognitive history of the emergence of modern architecture. Cutting across disciplinarian and institutional divisions as we know them today, it reconstructs developments within the framework of a cognitive history of the past. Modern is here taken to mean the radical re-thinking of architecture from the end of the tenth century in Europe to the end of the eighteenth century. Among the key debates that mark the period are those that oppose tradition to innovation, canon to discovery, geometrical formality to natural picturesqueness, the functional to the hedonistic. These conceptual changes are interwoven with institutional transformations which are also recorded here: the gradual separation of the architect from the ranks of the craftsperson, the increasing division between the professional categories we recognize today: architect, landscape architect, engineer and urban planner, the struggle of the designer to secure a position as an autonomous specialist, an intellectual, a free and critical commentator upon the state of human affairs. The hypothesis here is that by the end of the eighteenth century, when this documentary history ends, the conceptual, professional and educational structures for the practice and propagation of modern architecture are in place. The foundations of architectural thinking emerge essentially as they still are today.