Book excerpt: Long before he became the host of the tonight show, Jay Leno was dubbed by the media and his peers alike as the "Hardest-working Man in Show Business." Performing comedy at a breakneck pace, he played more than 300 dates a year and traveled to every corner of the nation. Or as his mother who never quite understood what he did for a living, liked to say, "Going from town to town, putting on his little skits."--