About a month before a Kremlin coup in October 1964 ended Nikita S. Khrushchev's 10-year reign as head of the Soviet Union, his son, Sergei, received an unexpected phone call from a former K.G.B. man tipping him off about the plot. In this very intimate ''inside the Kremlin'' book, Sergei N. Khrushchev also reveals that his sister Rada also had a call a few months earlier from a woman informing her that proteges of her father were planning his overthrow. She couldn't believe the information and the one person she told about it persuaded her that it was nothing to worry about.
Sergei, then involved in missile research, was intimately aware of Kremlin politics and took his informant, Vasily I. Galyukov, seriously but still found his warning hard to believe. And more than that, he was faced with a personal dilemma. His father had told him not to meddle in party affairs, and if he told him of the impending plot, he would not only be violating the taboo but would also be accusing his father's closest associates of conspiracy, a crime in the not-too-distant past that could have led to the firing squad.