Photoproduction of mesons and hyperons

Pions, heavy mesons, and hyperons were all first observed in cosmic‐ray interactions many years ago. Considering the rarity of the observed events and the difficulty of the experiments, an extraordinary amount of knowledge was obtained from this work. The rate of discovery of new particles and of excited states of particle systems increased rapidly with the development of high‐energy accelerators for protons and electrons, and the pace has now been very fast for several years. This report concerns some of the work in one section of the field, the photoproduction of mesons and hyperons.