This book does an exceptional job of describing the installation, configuration and optimization of Tomcat. It provides detailed commands and code samples that would be helpful to Tomcat administrators in maintaining and troubleshooting their server.
While the introduction says the book isn't necessarily just for administrators, that's where it has the most value. What I was hoping for was more information as to how Tomcat works to process requests and deliver responses. One section of the book I did find helpful was the chapter on clustering and improving server availability.
Overall, I think this is a great reference for someone that is responsible for the regular performance of one or more Tomcat servers but doesn't provide a completely rounded overview.