Instruct: Classify Amazon reviews into positive or negative sentiment
Query: The best PostgreSQL book on the market, but not perfect.

I can't give this book 5 stars. But I can give it 4. Compared to all the other PostgreSQL books, its the best compared to the rest....But its problematic to buy a PostgreSQL book at this time (December 1, 2002) because of versioning. Currently, the newest version out is 7.3. But all these books as of this posting are based on version 7.1 or below ugh... hopefully this is a minor issue. Too bad there are very few books to choose from... but after reading and studying the few pgsql books on the shelf, this is the winner.