In the book, Obama acknowledges that he used cocaine as a high school student but rejected heroin. "Pot had helped, and booze; maybe a little blow when you could afford it. Not smack, though," he says.
In an interview during his Senate race two years ago, Obama said he admitted using drugs because he thought it was important for "young people who are already in circumstances that are far more difficult than mine to know that you can make mistakes and still recover.
"I think that, at this stage, my life is an open book, literally and figuratively," he said. "Voters can make a judgment as to whether dumb things that I did when I was a teenager are relevant to the work that I've done since that time."