I thought it might be interesting to mention here some personal recollections of the prehistory and early history of string theory. These reminiscences are presented in an informal manner, as if they were a contribution to oral history, without the usual footnotes and references of a scientific article.

I have always been a strong supporter of string theory, although (especially early on) I did not know exactly, any more than others did, how it would be useful.

During the Seventies and Eighties, in accordance with my role as an ardent conservationist, I set up at Caltech a nature reserve for endangered superstring theorists. I brought John Schwarz and Pierre Ramond to Caltech and encouraged André Neveu to visit.

Over the next few years we hosted Joël Scherk and Michael Green and a number of other brilliant long-term visitors. Some of our graduate students became distinguished superstring theorists. Between 1972 and 1984, a significant fraction of the work on superstrings was done at Caltech, but I myself did not carry out original research on superstrings. Earlier, however, I did have a connection with the prehistory of string theory.

During the Sixties I regarded somewhat favourably the bootstrap approach to the theory of hadrons and the strong interaction, as put forward by Chew and Frautschi. It was connected with the mass-shell formulation of quantum field theory. I had proposed that formulation in the mid-Fifties and described it at the Rochester Conference on High Energy Physics in 1956.