And then he burst into tears, or as Russayev puts it in a BBC interview broadcast in 1997: "He cracked. Maybe he just let out all the tension, and he began to cry."

What we've learned: Critics wonder about Venyamin Russayev. He was, they say, one of several KGB agents assigned to "mind" Yuri Gagarin. There is no way to check his very personal accounts of conversations he says he had. Doran and Bizony stand by him. "Russayev told us a story that was entirely credible," says Piers Bizony. "We regarded him as a decent and reliable source." One reason they trust him, Bizony wrote me, is that "we were directed towards him by someone impeccably close to Gagarin, whom I cannot name." Others think he's a blowhard whoexaggerated to become part of space history.

Chapter 4: Can't Let Komarov Die

What the book said: Gagarin was just as anxious to save Komarov. On launch day, April 23, 1967, he showed up at the launch site and demanded to be put into a spacesuit, though no one was expecting him to fly. A Soviet journalist who was there, Yaroslav Golovanov, called this behavior "a sudden caprice." Was Gagarin trying to muscle onto the flight to save his friend?

What we've learned: Critics say this never happened. Gagarin would never demand a sophisticated "space suit" for a mission that didn't require him to walk in space, says historian Asif Siddiqi. The authors agree that the behavior was odd, but they have an eyewitness. In the BBC broadcast, Pravda journalist Golovanov