Mary Norris is a copy editor at The New Yorker and her new book Between You and Me, Confessions of a Comma Queen, is full of practical advice, and Norris's funny descriptions of some of the most common and vexing problems in spelling, punctuation, and usage. She deals with comma faults, danglers, "who" vs. "whom," "that" vs. "which," compound words, gender-neutral language-- and offers clear explanations of how to handle them. Amy Vince hosts the interview on The Point.