Two new thrillers from veteran bestselling writers—Tami Hoag and Martha Grimes—are coincidentally set in horse country—in Wellington, Fla., and in Great Britain, respectively. In both, the drama centers around a missing young girl. Hoag's latest, Dark Horse, combines her two passions, crime writing and horses; she is a competitive equestrian. Bantam published the book with a 300,000-copy first printing. The Grave Maurice is Grimes's 18th Richard Jury mystery; she began a 10-city tour on September 5. Viking printed 83,000 copies of the new bestseller. Her previous Jury mystery, The Blue Last, out from Onyx, has 300,000 copies in print.