the third book in the series Adventures in the Worlds of In And Out. The magical In children again visit Henry and his granddaughter Peggy by exiting a small hole in the hillside behind Henry's house. They 'form' to the natural size of children in Peggy's World of Out and are eager to return to Mammoth Cave, this time to hunt for ghosts. Cave explorer and author, Roger Brucker, says this book is "A first class cave mystery with clever twists, and sleuthing . . . . a sequel to the thrilling cave rescue of the author's previous Mammoth Cave book, Kids to the Rescue. So come along and watch Henry and the kids change size, sometimes all the way down to an inch high, which is just right for finding cave ghosts.