The Moonstone Castle Mystery, Nancy Drew Mystery Stories, number 40 in the series. Author: Carolyn Keene. Hardcover, 178 pages. Publisher: Grosset & Dunlap, no 9540, published in 1963.
The book covers, spine, and inner pages are all in very good condition. The binding is in fair condition and 2 pages (165/166, 167/168) are loose from the binding.
From the book: "When Nancy Drew receives a valuable moonstone as a gift from an unknown person, she is amazed and puzzled. But it is only the first of several startling events in this complex mystery..."