Instruct: Classify Amazon reviews into positive or negative sentiment
Query: Absolutely incredible!

I've used several EKG texts over the years and this one is definitely one of the best! The unique method used to convey basic through advanced EKG principles is highly effective! This book contains excellent diagrams to help reinforce concepts. The presentation of axis and 12-lead EKGs is especially helpful. I certainly don't think this is only book one should use when learning EKGs (i.e., Thaler's text is good too), but I think it's truly one of the best and most useful.