Instruct: Classify Amazon reviews into positive or negative sentiment
Query: Make sure you buy the 2nd Edition

Most of the reviews here seem to relate to the first edition (which was admittedly kind of short). The book has been updated, and the second edition covers new stuff like XSD Schemas, Diffgrams, SOAP Virtual Names, and all the other SQLXML 3.0 features. I found the book really useful, and easy to read. The examples are great and the concepts are all well explained. Definitely worth buying if you're planning to use SQL Server's XML functionality.