The third edition of Dr Klemperer's Electron Optics was published in 1971. It is concerned primarily with the experimental aspects of electron optics. It introduces the student to a specialized topic, and summarizes the basic principles and essential data related to the subject. With the assistance of Dr Barnett, this third edition discusses methods of trajectory tracing by digital computer and the optics of quadrupole lenses. Practical applications of electron optics have been used to illustrate the principles under discussion. The book will be of interest to any scholar of general physics, geometrical optics or electron physics. The extensive bibliography lists the more important original literature and provides a guide to further reading.