Two of the most significant microscopy milestones that were achieved in the last century were the imaging of individual atoms and the identification of individual atoms. Both these remarkable achievements were due to Prof. E. W. Miiller and members of his group at Pennsylvania State University. Almost fifty years ago, Miiller introduced a new type of microscope in which a sharp needle-shaped specimen was pointed at a fluorescent screen, Fig. 1. By applying an appropriately high positive voltage to the specimen, image gas atoms near the apex of the specimen could be ionized and radially projected towards the screen where they produced highly magnified images of the specimen surface, Fig. 2. By cryogenically cooling the specimen and using helium as the image gas, the first images of individual atoms were obtained in a field ion microscope by Bahadur and Müller on October 11th, 1955.