SEM—past, present and future

SUMMARY The development of the technology of the scanning electron microscope (SEM) is traced from the early pioneering work in the 1930s to the present day. Recent trends are described and, based on these, some speculative forecasts are made of possible future developments. It is suggested that these will include better vacuum conditions in conventional SEM to permit more accurate surface characterization, and improved electron optics for higher resolution, particularly with low‐voltage operation.