Jill Watson Glassco. Bloomington, Ind.: WestBow Press, 2013. 44 pp. (Large paperback). "Secrets of Shiloh,” by Birmingham author Jill Glassco, is billed as a mystery story for older children and teens. The first thing the reader notices is the incredibly beautiful illustrations — watercolors done by Birmingham artist Donny Finley. The book isn’t about the illustrations, though — it should…