Peter Reyner Banham (1922-1988) was a prolific architectural critic and writer best known for his 1960 theoretical treatise "Theory and Design in the First Machine Age", and his 1971 book "Los Angeles: The Architecture of Four Ecologies" in which he categorized the Angelean experience into four ecological models (Surfurbia, Foothills, The Plains of Id, and Autopia) and explored the distinct architectural cultures of each ecology.

He was based in London, moving to the USA from 1976. He studied under Anthony Blunt, then Siegfried Giedion and Nikolaus Pevsner. Pevsner invited him to study the history of modern architecture, giving up his work Pioneers of the Modern Movement. In Theory and Design in the First Machine Age (1960), Banham cut across Pevsner's main theories, linking modernism to built structures where the 'functionalism' was actually subject to formal strictures. He wrote a Guide to Modern Architecture (1962, later titled Age of the Masters, a Personal View of Modern Architecture).

He had connections with the Independent Group, the This is Tomorrow show of 1956 (the birth of pop art) and the thinking of the Smithsons, and of James Stirling, on the new brutalism (which he documented in The New Brutalism, 1955). He predicted a "second age" of the machine and mass consumption. The Architecture of Well-Tempered Environment (1969) follows Giedion's Mechanization Takes Command (1948), putting the development of technologies (electricity, air conditioning) even ahead of the classic account of structures. This was the area found absorbing in the 1960s by Cedric Price, Peter Cook and the Archigram group.

Green thinking (Los Angeles, the Architecture of Four Ecologies, 1971) and then the oil shock of 1973 affected him. The 'postmodern' was for him unease, and he evolved as the conscience of post-war British architecture. He broke with the utopian and technical formality. Scenes in America Deserta (1982) and A Concrete Atlantis (1986) talk of open spaces and his anticipation of a 'modern' future.

As a Professor, Banham taught at the University of London, the State University of New York (SUNY) Buffalo, and the University of California, Santa Cruz. He also was the Sheldon H. Solow Professor of the History of Architecture at the Institute of Fine Arts, New York University. He also starred in the short documentary Reyner Banham loves Los Angeles.

Banham said that he learned to drive so he could read Los Angeles in the original.