In most interviews, including the very start of this one, Daniel Radcliffe is so determined a spokesman for either Harry Potter or his stage roles that he's apt to come off as both energetic and impersonal. But when Jon Stewart brings up prematurely "jaded" youth, Radcliffe denounces it with genuine ebullience. He's self-deprecating and charming when describing how he summoned up the courage to tell Amy Poehler that he loves her in the cartoon show "The Mighty B." And after the host gets him to respond to the cheeky questions of some real-life Quidditch players, Radcliffe reveals a well of good humor, and an even deeper well of good sense -- and that also seems humorous, considering that he's at the center of such an insanely successful movie series. Radcliffe may be the rare child star able to sustain a versatile adult career even after playing a role as defining as The Boy Who Lives.