When Rudolf Mößbauer came to Lindau in 1979, he gave a lecture that was totally different from the four lectures he had given at the Lindau Meetings between 1965 and 1976. His first two lectures concerned the Mößbauer effect, the discovery of which had made him a Nobel Laureate and brought him to Lindau. The next two lectures indicated his change of interest as he moved from Munich to Grenoble, where he in 1972 succeded his PhD adviser Heinz Maier-Leibnitz as director of the Institut Laue-Langevin. This institute, which was founded in 1967 as a French-German initiative, has as its main instrument a small high flux nuclear reactor as a source of neutrons to be used for studies of materials, etc. But during his directorship, Mößbauer took an interest in a completely different kind of particle produced by the reactor, the neutrino. At the time of his lecture, two families of so-called leptons were established without doubt, the electron and its electron neutrino, and the muon and its muon neutrino. In his long historical and very pedagogical introduction, Mößbauer actually mentions the third family, the tau and its tau neutrino, but comments that they are not firmly established yet. In the second part of the lecture, he then describes a planned experiment to determine if an electron neutrino (actually its anti-particle) emitted from the reactor can change to a muon neutrino and back again. The idea is to have a movable detector for electron neutrinos and see if the intensity of detected neutrinos will oscillate as the detector is moved away from the reactor. The ILL reactor is not as powerful as a commercial nuclear power plant reactor, but Mößbauer mentions that for this particular experiment there is a bonus at ILL because the reactor core is so small that they can treat it as a point source. He also mentions plans to move the experiment to a more powerful reactor. By listening to his 1982 lecture you will find out which one! Anders Bárány