Web services, usually including some combination of programming and data, are made available from a business's web server for web users and other web connected programs. The accelerating creation and availability of these services is a major computing trend as software becomes increasingly distributed and web-based. Web services are the next logical step for web-based computing and will have a profound impact on the way in which business is conducted on the web in the future. As they involve many different systems communicating with each other, they are particularly important following the proliferation in the range of computing devices (PDA's mobile telephones, hand held computers etc). This book will provide a comprehensive treatment of the concepts and isses in web services, looking at how they are designed, and the key technologies, and standards used.