Architectural theory encompasses all the principles and concepts underlying the practice of architecture, from the fundamental theories of classical proportions to theories about the social or cultural role of architecture. It is therefore a wide-ranging subject upon which many architects and architectural historians produce essays, articles and reports.
Some architects come to prominence as theorists as well as practitioners. One such is C.R. Cockerell (1788-1863), whose buildings are now widely admired but whose commitment to the principles of Greek Classical architecture in the Victorian Gothic era won him few commissions. The papers of Cockerell include his lecture notes for the Royal Academy lectures, from 1841-1856, which contain his wealth of knowledge and convictions about the importance of classical principles. Cockerell's letters to his family and friends written during his tour of Europe, 1810-1817, are also full of his thoughts about the principles underlying the architecture of the continent, Italy and Greece in particular.
Personal correspondence often includes discussions on various theories and concepts. In his letters to his wife, Sir Edwin Lutyens (1869-1944) refers to his beliefs about truth and beauty and these are clearly concepts underlying his approach to design. Charles Holden (1875-1960) writes on the principles of architecture, the role of the architect and the architect's duty to the client; Denys Lasdun (1914-) writes on the need for something more than reason to underpin the actions of the architect.
Some architects document their views in their own personal record. Berthold Lubetkin (1904-1990), an architect with a great belief in the social responsibility of architecture, compiled several notebooks full of passionate and philosophical convictions about architecture and its relation to art and society in general. Data such as this is raw and unadulterated and far removed from the polished content of published sources.
Essays and notes for lectures and articles by architects and architectural historians may provide relevant information on architectural theory. The Collection includes the papers of Sir John Summerson (1904-1992), Charles Handley-Read (1916-1971), Stephen Welsh (1893-1976) and a number of other historians. There are, for example, lectures on art and architecture by H.S. Goodhart-Rendel (1887-1959), texts on accoustics in buildings by Hope Bagenal (1888-1979) and notes on colour theory by MGF Ventris (1922-1956).