Our guest on Tuesday's AU is Mary Norris, who has spent more than three decades in The New Yorker's copy department. She's out with a new book "Between You & Me: Confessions of a Comma Queen" in which she addresses some of the most common and vexing problems in spelling, punctuation, and usage―comma faults, danglers, "who" vs. "whom," "that" vs. "which," compound words, gender-neutral language―and explains how to handle them.