Instruct: Classify a review as either positive or negative.
Query: A very, very good pocket reference

This is the first time I've given any book five stars. That's because this is the best pocket quick reference of VI you're going to find. The information is presented as concisely as it can be and still remain accessible. Other, terser (and, yes, less expensive) quick reference cards for VI are too cryptic to be useful, in my opinion.If you don't already know VI, try an on-line tutorial (there are plenty) or buy the more complete "Learning VI" book from O'Reilly to get you started. After you've acquired the basics, periodically refer to the Pocket Reference to add yet another "I didn't know VI did that" command to your toolkit.