Instruct: Classify the given Amazon review into positive or negative sentiment.
Query: an interesting look at an old mystery

I have been intriqued with the idea of ancient celtic contact with the New World ever since reading America B.C. I am impressed that the authors have taken this unusual approach of looking at the enigmatic barrows from a "paranormal" viewpoint, rather like a mystery that surrounds a mystery. If there is any deficiency that I have found it is that they authors seem to begin more with the assumption that the barrows are of ancient celtic origin and work from there, rather than spending more time supporting their conclusions regarding their origin. Still, it is enough to spark the imagination and, hopefully, to preserve these mysterious sites for the future.