I mentioned that- how much I am indebted to Jan Klein, for the material that he has just provided and I want to say a word about Jan Klein himself because that takes me back to my Prague connection. I have mentioned that Milan Hasek was a meteoric figure in science in Prague and I think responsible for holding the fort for decent science in the Czech Academy of Sciences, through his position in the Czech Academy of Sciences, in the dark years of Prague. The Velvet Revolution took place in 1968 and at that time, some Czech scientists who had been abroad stayed abroad, some of them stayed in Prague. Milan Hasek was uncertain about what to do, I remember him- I very well remember him sitting in our kitchen in Mill Hill- National Institute- where we lived near the National Institute of Medical Research, and we spent an afternoon, Lorna and I, talking with Milan about his plans, and he- we, of course, said to him if he wanted to stay in the West, in Britain or America, it would be easy for him to find a position in which he could go on working, but we both urged him to go back to- to Prague. Well what were our motives? I don't think that only we were thinking about his well-being at all, I think we were thinking about the well-being of science and the well-being of personal, intellectual endeavour in a totalitarian- under a totalitarian regime. Just a- a little cross mention here- during my time in Prague the most sympathetic character- well, Milan was a very sympathetic character in his own way but he was a big boss then, he had other things to do. The most sympathetic person was Miroslav Holub, who is well known now in the West as a poet, less well known as an immunologist, but he was working for Milan or in Milan's section, and we became good friends, and it became clear to me that his- he was just as interested in poetry as he was in science. Very unusual, I didn't- never met anybody else with those interests, and I am very proud of having become a friend of his there. Maybe the best time I ever had in Czechoslovakia was going on a holiday with him and his girlfriend through the Nízke Tatry, the Low Tatra Mountains, where you could walk for days through the fields of- with black fruit growing in them and one's trousers became stained purple from the bilberries. Anyway, Milan's being- sorry, Miroslav was going on about the realities of totalitarian life, and his girlfriend who was no more sympathetic to the regime than he was, but kept telling him, reminding him, that there were positive parts of the communist regime in Prague, and of course there were. If only the Russians had kept their noses out, Czechoslovakia would have had a left wing, or might have had, a decent left wing government in which all good things could happen. Anyway, in 1968 that looked like a real possibility under Dubcek. The Russian presence diminished, but then the Warsaw tanks moved in and crushed the Velvet Revolution, so Milan- I don't think it was- I don't think it was our fault that he went back- but he did go back and within a few years he was miserable and he was drinking and eventually he drank himself to death. But others stayed out, Juraj Ivani and his wife Leda, who had very positive scientific careers in Britain- they've done- they made very useful contributions to the development of immunology in Britain. And I think they would all agree that the top of the heap was Jan Klein, who moved to America, first to Michigan where he collected his wild mice, and then to other places in America. And then, too, he was invited back to Europe to be Scientific Director of a Max Planck Institute in Täbingen Abteilung Immunogenetik. Very successful that has been too in sorting out the mouse MHC properly, and in a way the best relic for me in my Prague connection is to be a friend of Jan Klein's and just in the last few years he has turned up trumps through- with his wild mice MHC genes.