This book has everything to know about .NET web services. The coverage is perfect for any average user, just at the correct level of detail. Neither too deep to make you bore nor shallow to disappoint you. I am currently designing web services for my company and it helped in areas such as - passing and returning complex data types in a web service method, asynchronous web services, caching, etc. The writing is simple and easy to follow. The sample code is in C#.
The only disappoint I have with this book is that it does not cover the publish/subscribe or event notification mechanism in any detail. Looking at the time this book was written, I can understand why these were not covered. Otherwise excellent book.