I think the title and cover of this book are slightly misleading, since it would appear a bunch of kids gets lost on a mountain, which isn't really what the book is about. It starts out with quite a bit of excitement, but then the pace slows for a huge part of the book while the kids do research and plan. Then the ending picks up again.Clearly there's meant to be a sequel, since there are many unanswered questions and dropped hints, so many that I wonder how they can all be answered. Is the librarian really evil and somehow from the past? (As a librarian, this question especially concerns me.) I did like the author's note and the historical elements of the book.If there are elementary-school kids looking for an adventure story, this fits the bill. I just wouldn't describe it as fast-paced.The audio version was OK, but as it went on, I found that both Jack's and the mom's voices started irritating me.