The 1956 Lindau Meeting included three interesting lectures on theories of elementary particles by physicists actually working in the field: Paul Dirac, Werner Heisenberg and Hideki Yukawa. And, in the audience, there also were two other theoretical physicists with similar interests, Max Born and Wolfgang Pauli. For Pauli, this was his only Lindau Meeting (he passed away in 1958) and since he didn’t give a formal lecture we miss his voice in the Mediatheque. But he is present in Yukawa’s lecture, as is Born and (in particular) Heisenberg. As a true gentleman, Yukawa repeatedly makes reference to Heisenberg’s lecture, even though Yukawa’s understanding of spoken German was limited. In his lecture he first mentions that since last time he lectured in Lindau, in 1953, the number of new particles had increased tremendously and that there was a strong need for a better understanding of the new quantum numbers introduced to keep track of all the new particles. Yukawa tries to argue that many of the new particles could be composite objects and that the number of what he calls “really elementary” particles could be much smaller. As examples of “really elementary” particles he mentions protons, neutrons and the gamma particle, which was the particle which lead to the introduction of the quantum number strangeness. Today, of course, we know that all three of these particles are composed of quarks. But Yukawa’s lecture acts as a time machine and shows how physicists thought about the “zoo” of new particles found after WWII. Somewhere in the middle of his lecture, Yukawa becomes very technical and mainly speaks for his Nobel Laureate colleagues. This means that he probably lost most of the young and mostly German reseachers in the audience. But for them it might still have been a good language lesson, since Yukawa speaks slowly and in very good English!