Instruct: Classify Amazon reviews into positive or negative sentiment
Query: What this book is good for

This is not a how to or tutorial book. It was written to convey the specifics of the ECMAScript standard so that web developers who are writing script can be assured of the highest level of browser compatibility. It you have to write a truly "run anywhere on anything" script, you should have this reference. Just don't read it when you are sleepy.The four star rating is not due to a lack of quality. As a PerfectScript programmer, I can tell you that Gordon McComb always does quality work. However, you can only do so much with a very dry and technical subject.