I tried to improve my analysis at various stages. I mean I did at one stage go away and plough my way through Dunford and Schwartz, you know, learn all about operator theory and so on, but I picked up a lot of it by just talking to Singer and he would explain things and I would understand them. So most of it was by osmosis like that, but I did make attempts to read one or two books. I read, needless to say that I read Gelfond and Naimark book on normed rings because – C*-algebras – and that was… Singer was very good at it, so I did actually make attempts to sort of read a few serious books.

They were about the first books I'd actually tried to read since I was a student, you know. After you've ceased being a student you don't usually read textbooks; you learn what you need to on the hoof. But since my analysis hadn't been particularly good, I thought I did need to go back to square one and I did actually make a serious attempt to learn a bit. Then subsequently I read Hörmander and other things, and pseudo-differential operators. Yes, so I did try to supplement what I'd picked up from Singer by filling in on the analysis. But all generally with the aim of things related to the analysis I needed on elliptical equations, although subsequently I got interested in hyperbolic equations, so I, you know, branched out here and there in different directions. But it was a mixture of talking... talking to him and then backing it up with some additional reading, yes.