Instruct: Classify Amazon reviews into positive or negative sentiment
Query: Excellent, one-of-a-kind, and useful

This is a very handy book for the clinician to deal with the unusually type of disease. Porphyria is not a daily household word and so finding any information is hard-to-come-by and this handy book is authentic, informational and easy to understand and could only be written by someone who deals with the disease on a daily basis. I have recommended it for patients now that I have read it. It is the best there is out there on the subject.