This work originated in a series of lectures on meson and baryon ex­ cited states which I gave at the Stanford Linear Accelerator Center in the fall of 1962. The notes of these lectures were issued as a Stanford Uni­ versity report (SLAC-13) in March, 1963. In the fall of 1963, I gave a revised set of lectures on meson and baryon spectroscopy at Indiana University. In both cases, the talks were given primarily for experi­ mental physicists. In preparing the notes of these talks for pUblication, I have added some introductory material on pions, nucleons, kaons, and hyperons. My main emphasis is on the experimental facts concerning the spectros­ copy of the mesons and baryons and on the use of conservation laws in their interpretation. I have either mentioned briefly or omitted entirely explanations which depend on dynamical models. Although I have given a number of facts about the electromagnetic and weak decays of some mesons and baryons, I have not discussed the theory of these decays. This is not a comprehensive review of the subject of the strongly interacting particles, and the list of references is not complete. Also, I have not always devoted time to a subject in proportion to its impor­ tance, but have spent more time on topics which have particularly interested me. Nevertheless, I hope that I have provided a useful summary of the most important facts about the spectroscopy of the mesons and baryons.

Preface.- 1. Introduction.- 2. Conservation laws.- 3. Methods of obtaining information about the spins of particles.- 4. Methods of obtaining information about the parities of particles.- 5. Adair analysis and generalizations.- 6. Dalitz plot and other plots.- 7. The nucleon.- 8. The pion.- 9. The ? hyperon.- 10. The kaon.- 11. The ? hyperon.- 12. The ? hyperon.- 13. Selection rules.- 14. The ? meson.- 15. The ? meson.- 16. The ? meson.- 17. The K* meson.- 18. The ? meson.- 19. Some other mesons.- 20. Effects in the ?? and K $$ar K$$ systems.- 21. Excited states of the nucleon.- 22. The ? (1385) hyperon.- 23. The ? (1405) hyperon.- 24. The ? (1520) hyperon and the parity of the ?.- 25. The ? (1660) hyperon.- 26. The ? (1815) and the K--nucleon cross section.- 27. The ? (1530) hyperon.- 27a.The ? hyperon.- 28. A classification scheme.- 29. Possible violation of C P invariance.- 30. Recently discovered meson states.- 31. Recently discovered baryon states.- 32. Recent measurements of particle masses, lifetimes, and decays.- 33. Classification according to S U6.- References for sections 1-28.- References for sections 29-33.