The conversations with Landau and his group – although we… they were carried on in a very friendly manner, didn't get anywhere. They kept saying, ‘Well, show what's wrong with our method.’ We said, ‘Well, your method is just adding up a few leading logs. Now, we looked into it more deeply. We have this formula that applies to all orders and presumably is non-perturbative. And you can see that the different cases depend on what happens to the ψ of x function at very large x–some people would say β/^x at very large ^x but it's the same thing. And you… and you can't possibly tell that from the first few orders of perturbation theory.’

[Q] Were you impressed by Landau?

In a way, but I generally like people who are more open, and I was much more impressed therefore with Yakov Zel'dovich. But of course over there in the pecking order Landau was much higher than Zel'dovich and Landau used to make fun of Zel'dovich all the time. In fact, there's a terribly sad story that's also funny. You know that Landau suffered this horrible automobile accident between Moscow and Dubna, and his brain was very seriously damaged. He couldn't really do scientific work any more after that and he’d lost a lot of short-term memory. I couldn't bear to go in and see him after the accident in ’64, but I was told that if I had he would probably have recognized me and spoken to me in English, but that a minute or two later he wouldn't have remembered that… that he had spoken to me and he would say hello all over again and so on. It's terrible. But anyway, the story is that after he recovered a bit from the accident and was able to talk and so on, one of the first things he said was ‘I'm afraid my brain is just not the same as it was. I'll never again be able to do physics like Landau. Maybe I could do physics like Zel'dovich.’ But anyway, I really preferred Zel'dovich because it seemed to me he was a much more open, much more flexible person. Landau was so stubborn.