Instruct: Classify the given Amazon review into positive or negative sentiment.
Query: the best of its kind...

The Pictorial Guide to the Living Primates is the most complete book of its kind that I've been able to dig up. Most others seem to go into great detail about SOME of the species, and give little or no mention about others. Rowe's book is very useful in that it will give at least some information about any known species. It is pricey, but in relation to other books about primates in general, this one is as close to being 'worth it' as they come.