Instruct: Classify Amazon reviews into positive or negative sentiment
Query: Couldn't put it down

As other reviewers have mentioned, there were some slow parts (ie. historic details pertaining to the setting), however, overall I couldn't put this book down. The twisting plot kept me guessing and rethinking about earlier clues in the book - definately need to read carefully. The ending was shocking and I stayed up all night finishing this book. I hope that this is just the beginning for Fergusson. This book was not at all what I expected when I picked it up - not your average thriller.