This book does not go into great depth for each of the techniques - SOAP, XML, XML-RPC, and so on - and it should not. This book is great if you want to get the helicopter view - how do these techniques fit together, so that you can build a whole application. The examples are short and succinct, and can be read while sitting / lying in your favourite reading place. If I have to name one bad thing, then it is that this book tries to take on a such a big area, that it misses on some smaller bits, for example Sun's Java XML pack, because that came out after this book was published.