The Crystal Cave.

I'm talking about The Crystal Cave, a novel about Merlin by Mary Stewart. This was one of my favorite books as a teenager and my 13-year-old recently decided that he's ready to read it too. So we looked for the copy we have. We couldn't find it. We decided to just check it out of the library. When we got there, we couldn't find it on the shelves, so we asked the librarian. She couldn't find it either. It was supposed to be there, but wasn't. So, off to the bookstore we went (there's only one bookstore in our small town). They had all 3 of the other books in the series but not The Crystal Cave. We're starting to feel like maybe this isn't a good time to read this book?