I've forgotten how much later it was that I had the pleasure of meeting the two leaders of the Soviet H-bomb project, Yakov Borisovich Zeldovich, and Andrei Sakharov. We never discussed the gadget at all. We were interested in questions of principle in physics and questions of peace in the world. Sakharov, as many of us know, was a man of deep principle. He, for speaking up as he did, was exiled to the city of Gorky. And later, after he was released from exile, a few months afterwards, I had the pleasure of dinner with him at his apartment in Moscow, and I learned about how the release had come about in December, at eleven o'clock at night, there would come a knock on the door of his apartment in Gorky, it was the Russian secret police, the KGB. They had told him they were going to install a telephone. They had received orders from Moscow to do that because an important personage, as they put it, was going to call Sakharov in the morning. Well, Sakharov was all ready when the call came through, from Gorbachev, at eleven o'clock the next morning. He didn't wait for any politenesses. "Professor Sakharov, this is your Chairman calling." "Oh, Mr Chairman, I have to ask you for your help. There are six people in the world of physics who have been put in prison in this past week for their political opinions. It's a disgrace to science, a disgrace to Russia, disgrace to the world. They should be released." "Well, Professor Sakharov, we're making arrangements for the head of the Soviet Academy to come to Gorky and take care of your move back to Moscow." Not a word of thanks from Sakharov, he immediately replied "Oh, Mr Chairman, there are over 500 people in prison now for their political opinions, they should be released, Mr Chairman." and he hung up, like that. No more... sweet nothingnesses. Well, here he was, I was talking to him in Moscow, and it was quite something to see his apartment that he had only just moved into, here on the floor was a heap of letters, maybe so big around and so high, letters from people all over Russia, poor people asking him for help getting somebody free, or otherwise putting a burden on him. And the poor man, a man of great conscience. His father had been a priest in the Orthodox church, so he had the bringing up as a matter of principle much in his background.