Instruct: Classify the given review as either positive or negative.
Query: A black magic novel with some basis in truth

The author has steeped himself in the ancient basis of the occult through extensive research and by actual contact with those who perform "The Secret Art". Wheatley has become one of the few writers qualified to describe the rites of the occult- the Black Mass, how Satanists snare recruits, how they blackmail the unwary, the acts of appalling blasphemy, and the bizarre sexual rituals performed in their secret temples.