I found this to be a very valuable reference, as well as a quick-start on JSP, Servlet and J2EE presentation-layer architecture.
I like the author's no-nonesense approach and explanations in terms of real platforms (eg: JRun and Tomcat servlet engines).
The book is well structured, comprehansive, well focused on JSP/servlet layer, and provides the reader with exactly what it says in the title: "The complete reference to JSP".
Wish other authors could also be precise, rather than trying to be "JSP, Servlet, EJB,Italian cooking and..." and running into 1000+ pages of words with little content.