Instruct: Classify Amazon reviews into positive or negative sentiment
Query: Incredible read!

A fantastic book. I am so happy I purchased it. Not only does this book give the reader a comprehensive look into "Operation Drumbeat", but the Battle of the Atlantic and U-boat operations overall. Not only was this book an enjoyable read, it is also an invaluable source of information regarding details of the U-boats' machinery, equipment, etc. The author does an excellent job of weaving this information into the story so it does not come across as if one is reading the owner's manual to a new car. I have always considered "Iron Coffins" to be my favorite book on U-boats, and while I still consider it an excellent read, "Operation Drumbeat" has without a doubt moved to the top of my list in this area. I highly recommend this book to anyone interested in U-boat warfare during the Second World War.