In this brief survey I am going to borrow some ideas from a lengthy review prepared in collaboration with Murray Gell‐Mann and Arthur Rosenfeld for publication elsewhere.* In the title of our article we have used the term “particle” but have carefully avoided the adjective “elementary”. Had the title of my paper here today been of my choosing, I should similarly have avoided such a modifier, because if there is a discernible trend in current high‐energy physics it is the decline of the elementary particle concept. A major purpose of my report to you is to describe this decline of an ancient idea and the beginnings of a new idea that may fill the void.
This review of the recent evolutionary history of particle physics is based on a paper prepared for delivery in Washington, D.C., on October 22, 1963, as part of a program of invited lectures presented during the centennial celebration of the National Academy of Sciences. Professor Chew's paper, together with others presented on that occasion, will be published in the forthcoming Proceedings of the Academy's centennial meeting.