Instruct: Classify Amazon reviews into positive or negative sentiment
Query: A very poor book for teaching DirectX.

From all appearances DirectX seems to be a extremely clumsy and tedious interface. The author works around this by wrapping all the DirectX details in his own classes. While this might be a good tactic if you are a progammer, it doesn't work when you are actually trying teach the DirectX interface. If his classes where very, very good then one might be tempted to just use them and forget about DirectX entirely. Unfortunately they are not that good.