Wireless Java is a fast-moving area, with almost daily changes to APIs, SDKs and new devices. It is further complicated by the many different Java platforms that exist. In such a situation, it is customary to explain the context of the technology, and a 'roadmap' - where we've come from, where we are, where we're going. An experienced developer also requires a well-structured guide to building simple applications of different kinds (in the case of Wireless Java, these would currently be for J2ME, Symbian's own UIQ, and JNI - connecting Java and C/C++ etc together).
While there is a lot of information in this book, it is presented in a haphazard and rather long-winded way, and makes learning new things a daunting task. Many of the examples are incomplete, finding them on the Web is difficult (there is no CD), and some of them do not compile for all platforms. The build process, crucial to deploying an application on the phone, and relatively simple to explain, is, incredibly, omitted.
The book's coverage of J2ME is minimal. You'll like this book if you're just trying to fill in some gaps in your knowledge, but don't expect a gentle or organised introduction to writing for Symbian devices.