Instruct: Classify Amazon reviews into positive or negative sentiment
Query: Interesting, but a bit thin on real substance

One of the disadvantages of reviewing something after 1,000+ other people have already posted their observations is that there's nothing left to say that hasn't already been said numerous times. So I'll keep my comments brief. "Freakonomics" is not a book of great substance. In it, the authors explore a half-dozen topics, and offer some (perhaps) new insights into various matters. Some of what they say borders on the obvious (e.g. realtors don't really work for their clients' best interests; they work for their own best interests) while others fall into the "who cares" category (e.g. an overlong exploration of fixed matches in the world of sumo wrestling). Still, the book is a interesting read, and contains just enough new ideas to provide fodder for cocktail party conversations. I give it a low 4 stars overall.