The author has studied the origins of the modern movement in England, which he found extremely complex. Wells Coates was one of its leading protagonists: he played a great part in the various attempts to establish the resistance movement against 'ancestor-worship in design' out of which modern architecture has grown. He devoted his powers and passions to the growth of the movement in England, at a time when there was a mass of traditionalism and prejudice to be cleared away. Wells Coates was an engineer and scientifically minded; he was also able to express his profound belief in certain architectural principles. Through the 20th Century Group, and other groups, he helped to bring modern ideas in art as well as architecture to the British scene. His part in MARS and CIAM was especially directed at exploring the common ground between architecture and engineering; at the same time he was fascinated by the affinity between architecture and the fine arts and was one of the founders of Unit One. These ideas occupied his mind to the end of his life, when he envisaged a new organisation - 'CAUSA' and 'OUTLINES' - which would assemble all the branches of the visual arts against the central problems confronting contemporary architects, engineers, planners and designers. The same combination of qualities went into his architecture, with the addition of an equally profound habit of enquiry into the social as well as the technical functioning of his buildings. Acknowledging Wells Coates is, I think, vital. This study has been built up mostly from Wells Coates's own diaries, notes, letters, lectures and various memoranda; and from correspondence and meetings with some of his contemporaries and clients.