Instruct: Classify Amazon reviews into positive or negative sentiment
Query: Great book, if you know what to expect...

Think of this book like you would think of a dictionary -- not great reading material, but good to look stuff up in. Please do not think that this is a book for beginners. Like a dictionary, you need to have some idea of the language in order to get any use of it. If you are a current user of XML, then you will find this book to be a great reference to have for those times when you juuuuust can't remember the syntax (how to write a command so the computer understands it). After the syntax are good examples that put the command in perspective.