Instruct: Classify Amazon reviews into positive or negative sentiment
Query: A great and enlightening read!

I met Mr. Powlik at a book signing last weekend in Salisbury Maryland and bought his book. I've already finished it and had to write to say how much I enjoyed it. There are a lot of interesting science and ecological issues woven into the plot. Because I live near the Chesapeake Bay, I am especially interested in the subject of Pfiesteria and its threat to our environment. Thank you Mr. Powlik for helping to raise awareness about these issues. But back to the story...it's gripping and moves at a great pace. I thoroughly enjoyed reading this book and I have several friends who would love it. Looks like some of my Christmas shopping is done.