I am presumably here to give you my perspective on quantum field theory from the point of view of a condensed matter theorist. I must begin with a disclaimer, a warning that I may not be really representing anyone but myself, since I find myself today working in condensed matter after following a fairly tortuous route. I must begin with a few words on this, not only since it will allow you to decide who else, if any, I represent, but also because my past encounters with field theory will parallel that of many others from my generation.

I started life in electrical engineering, as Professor Schweber said in the introduction. As an electrical engineering student, the only field theorists I knew about were Bethe and Schwinger, who had done some basic work on wave guides. When I graduated, I switched to physics and was soon working with Geoff Chew at Berkeley on particle physics. In those days (sixties and early seventies), the community was split into two camps, the field theorists and the S-matricists, and Geoff was the high priest of the latter camp. The split arose because, unlike in QED, where everyone agreed that the electron and the proton go into the Lagrangian, get coupled to the photon and out comes the hydrogen atom as a composite object, with strong interactions the situation seemed more murky.