The amiable Mercy Watson takes an automobile ride she'll never forget in the second tale of an ebullient first chapter-book series by Kate DiCamillo and Chris Van Dusen. Mr. and Mrs. Watson's porcine wonder, Mercy, loves nothing more than a ride in the car. It takes a fair amount of nudging and bribing and a "You are such a good sport, darling" to get the portly pig out of the driver's seat, but once the convertible is on the road, Mercy loves the...