Instruct: Classify the given Amazon review into positive or negative sentiment.
Query: Could not put it down

Picked up this book out of boredom, and could not put it down. Read it in one day. As a true crime nut, I have occasionally toyed with the idea of writing to a serial killer (Manson would be first, I'd always thought) and this account made me glad I never have. Absolutely fascinating and frightening. Didn't give it 5 stars because it was also very disturbing, and not something I would want my mother to read. Wow.