Book excerpt: Winning came naturally for Al Unser, Jr. He had a gift for finding the fast line on the track and he possessed a boisterous and lovable personality. Fans and the press adored him. Behind this affable persona, an appetite for drugs and alcohol was destroying his private life. Unser's battle to climb out of that cave is one of the great stories in motorsports. A Checkered Past is an unblinking story of triumph, tragedy, and the road to recovery.