content: This is not a how-to, it is a how-to-understand. I own multiple editions of this book starting with the 3rd, when many of the examples referred to RBase. It won't tell you, with simple color diagrams and cut-and-paste examples, how to optimize your Oracle SQL queries or tune your DB/2 engine, but it will teach you the underlying principles of relational databases, from which the serious professional will be able to extrapolate. If you have the intelligence and stomach for it and you actually read it, it will serve you much better than the SQL in 24 hours picture books that some reviewers seem to be looking for -- it is a timeless and effective conceptual work on the subject that spans the evolution of commercial product implementations. Dilitantes and desperadoes, head for the Dummies aisle -- this one's not for you.