Salpeter was one of Peierls' students, one of the continuing exchange of PhDs between Peierls and myself. He came here and he obviously was very knowledgeable and we worked together. We knew the Feynman theory of quantum electrodynamics, but we said to ourselves 'Well, really one ought to be able to do this also for particles that interact strongly.' And, so we set out to... to do quantum electrodynamics in a... in an external field, let's say the field of an atom, strong field of an atom. And we convinced ourselves that one could generalize the quantum electrodynamics to include strong interaction, and we constructed an equation for two interacting... strongly interacting particles with the effect of the electromagnetic field included, and that became known as the Bethe-Salpeter Equation. We continued a little bit on that in rewriting the Handbuch article which I had written about one and two electron problems. Salpeter helped to generalize this to... to include relativity and quantum electrodynamics, and that produced the second edition which came out as a separate book. And we had a graduate student translate the old paper into English and added to it in English what we had newly found. So this was the Bethe-Salpeter edition of Quantum Theory of One and Two Electron Problems.

[Q] And, there were other people like Rohrlich?

Yes. Well, he became professor in Syracuse. Salpeter, as I have mentioned already, went into astrophysics and discovered how to make carbon atoms out of helium, and remained in... in astrophysics most of his life. There was Dalitz coming again from... from Peierls, who then became the chief assistant of Peierls at Birmingham and later on in... in Oxford.