Clay Aiken is far more interesting a person than a pop star and, God bless him, he's smart enough to know it. The 2003 American Idolrunner-up dispenses with his experience on the show (including, Claymates will be happy to know, the infamous ''Grease'' incident) in a few vague chapters toward the end of Learning to Sing. The bulk of the book/brand extension details his working-class North Carolina upbringing including his abusive, alcoholic birth father and his fascinating, steel magnolia of a mother, a source of comfort, inspiration, and holy terror. (We suggest a sequel: Mama Clay Tells All!) Behind the polite narration in Learning to Sing emerges a complex guy with a folksy sense of humor (''I was teased by other kids like it was their job'') and an endearing ambivalence about his own insta-celebrity.