Instruct: Classify Amazon reviews into positive or negative sentiment
Query: excellent

an excellent exposition of the folklore and phenomenology of this unique and disturbing experience. i, too, have experienced the teror by night, and until i read this book i never suspected it was so common and so ancient. hufford's tracing of the vampire legends and even the salem witch trial to this is eye opening. after reading it, i found other, independent references to the same experience in ancient mesopotamian texts. i highly recommend this book!!!