Charles Oatley made three outstanding contributions to the engineering sciences: he was one of the brilliant team that developed radar in Britain during the Second World War; he revolutionized the teaching of electronics at Cambridge University; and he developed the scanning electron microscope. It is for the last of these that he will be chiefly remembered. He stands with Manfred von Ardenne as one of the two great pioneers of scanning electron microscopy
His involvement with the instrument began shortly after the war when, fresh from his experience in the development of radar, he perceived that new techniques could be brought to bear which would overcome some of the fundamental problems encountered by von Ardenne in his pre–war research. Oatley's work led directly to the launch of the world's first series production instrument—the Stereoscan—in 1965.
Thousands of scanning electron microscopes have since been manufactured and are to be found in practically every research laboratory in the world. The striking three–dimensional images of microscopic organisms produced have been used to illustrate countless newspaper and magazine articles, as well as scientific research papers, giving the general public a new perspective and appreciation of the world that lies beyond the resolution of the human eye. The scanning electron microscope is, arguably, the single most important scientific instrument of the post-war era.