This book packs a lot into 400 pages, and is the most cutting-edge tags book I've seen. It uses a custom-built contact manager (all the code included) to demonstrate how the various components of a Java web app work together and how to deploy it using Tomcat. The app uses both MySQL and Access as its database, which should satisfy most readers. The illustrations explaining the servlet life cycle were excellent!
The book gives a thorough introduction to the various types of tags (simple, tags with bodies, cooperating, etc) and how they are used. Lots of practical code examples here. The illustrations in this part of the book very clearly explained the how custom tag components work together.
The Jakarta Taglibs coverage is very good, it is not exhaustive, but that's not bad since some of those tags should never see the light of day. I thought the author did a great job of picking the useful ones, explaining them, and providing code to demonstrate how they are used in combination. The coverage of the new Java standard tags is great, too. It includes info on the new expression language and how to change the language your tags use. Again, lots of good code to demonstrate usage.
Coverage of database concepts and tags was particularly good throughout this book. My only suggestion is to include even more code to demonstrate complex uses of the tags, but this would have made the book longer I suppose, and I do like that it is concise and easy to reference.
