In the late 1970s, at the IBM Research Laboratory in Rüschlikon, near Zurich, Heinrich Rohrer assigns Gerd Binnig, a newly arrived physicist, to investigate a thin-oxide problem related to a superconductivity project. Rohrer and Binnig, both trained in superconductivity and fascinated by the behavior of atomic surfaces, decide instead to build a completely new instrument based on quantum tunneling — the phenomenon by which an electron can cross an energy barrier that, according to classical physics, it should not be able to overcome — rather than adapting existing instrumentation. In January 1979 they file the first patent application. Christoph Gerber, who had been at the lab since 1966, joins the project to solve the critical technical problems: isolating mechanical vibrations and precisely controlling the position of a metal tip at a distance of just a few angstroms from a sample surface. Edmund Weibel, a research assistant, joins them as well. On the night of March 16, 1981, the team confirms for the first time that the tunneling current depends exponentially on the distance between tip and surface — the central physics of the instrument — and manages to externally and reproducibly control that distance inside a vacuum chamber. The first paper reporting the result is initially rejected by a prestigious physics journal following conflicting referee reports, and is finally published in Applied Physics Letters in late 1981. A second paper, "Surface Studies by Scanning Tunneling Microscopy", published in July 1982 in Physical Review Letters and signed by all four — Binnig, Rohrer, Gerber, and Weibel — demonstrates the instrument's true scope: for the first time in history, it becomes possible to obtain a real topographic image of a surface at atomic scale, resolving monoatomic steps and surface reconstructions on gold and other materials. The scanning tunneling microscope uses no lenses or radiation passing through the sample, as optical or electron microscopes do: a metal tip a single atom wide scans the surface at a constant distance, and the tunneling current flowing between tip and sample is translated into a three-dimensional map of the atomic arrangement. The technique opens for the first time the possibility of observing and, immediately after, manipulating individual atoms, and becomes the foundational instrument of nanotechnology as a scientific field. In 1986, five years after the first successful test, Binnig also develops, together with Christoph Gerber and Calvin Quate, the atomic force microscope (AFM), extending the technique to non-conducting surfaces.