Instruct: Classify Amazon reviews into positive or negative sentiment
Query: Good, but Outdated.

This book uses PostgreSQL 8.0 (or 8.1, maybe?), which is pretty outdated. Version 9.2 is out and has a lot of great features. I don't hold that against the book, but if you plan on learning and using the latest features of PostgreSQL, you may want to wait until a more recent book comes out. The official PostgreSQL site has great documentation that also includes a tutorial section (www_postgresql_org), so maybe you should look there first until the author update this text.