Former president Clinton remembered his grandparents and a college professor who taught him the importance of American values as important figures in his life. But it was Nelson Mandela, he says, who gave him the best advice he ever received. "He came out of twenty-seven years in prison a stronger, greater man than he was when he went in," Clinton wrote. "He said his transformation began when he realized his tormentors could take everything from him 'except my mind and my heart. Those things I would have to give them. I decided not to give them away. And neither should you.' "