microscopy (STED). Besides this technique a broad variety of other (not confocal based) super-resolution techniques are available like PALM, (d)STORM, SIM, and so on. They all have their own advantages such as ease of use, resolution, and the need for special equipment, buffers, or fluorophores. Low-temperature operability To image samples at low temperatures, two main approaches have been used, both based on the laser scanning confocal microscopy architecture. One approach is to use a continuous flow cryostat: only the sample is at low temperature and it is optically addressed through a transparent window. Another possible approach is to have part of the optics (especially the microscope objective) in a cryogenic storage dewar. This second approach, although more cumbersome, guarantees better mechanical stability and avoids the losses due to the window. Images History The beginnings: 1940–1957 In 1940 Hans Goldmann, ophthalmologist in Bern, Switzerland, developed a slit lamp system to document eye examinations. This system is considered by some later authors as the first confocal optical system. In 1943 Zyun Koana published a confocal system. In 1951 Hiroto Naora, a colleague of Koana, described a confocal microscope in the journal Science for spectrophotometry. The first confocal scanning microscope was built by Marvin Minsky in 1955 and a patent was filed in 1957. The scanning of the illumination point in the focal plane was achieved by moving the stage. No scientific publication was submitted and no images made with it were preserved. The Tandem-Scanning-Microscope In the 1960s, the Czechoslovak Mojmír Petráň from the Medical Faculty of the Charles University in Plzeň developed the Tandem-Scanning-Microscope, the first commercialized confocal microscope. It was sold by a small company in Czechoslovakia and in the United States by Tracor-Northern (later Noran) and used a rotating Nipkow disk to generate multiple excitation and emission pinholes. The Czechoslovak patent was filed 1966 by Petráň and Milan Hadravský, a Czechoslovak coworker. A first scientific publication with data and images generated with this microscope was published in the journal Science in 1967, authored by M. David Egger from Yale University and Petráň. As a footnote to this paper it is mentioned that Petráň designed the microscope and supervised its construction and that he was, in part, a "research associate" at Yale. A second publication from 1968 described the theory and the technical details of the instrument and had Hadravský and Robert Galambos, the head of the group at Yale, as