As a developer new to Web Services, how do you make sense of this emerging framework so you can start writing your own services? This text offers programmers both an introduction and a reference to XML Web services, first by explaining the foundations of these distributed services, and then by demonstrating quick ways to create services with open-source Java tools. Web Services make it possible for diverse applications to discover each other and exchange data seamlessly via the Internet. For instance, programs written in Java and running on Solaris can find and call code written in C# that run on Windows XP, or programs written in Perl that run on Linux, without any concern about the details of how that service is implemented. A common set of Web Services is at the core of Microsoft's new .NET strategy, Sun Microsystems's Sun One Platform, and the W3C's XML Protocol Activity Group. In this book, author Ethan Cerami explores four key emerging technologies: XML Remote Procedure Calls (XML-RPC); SOAP - the foundation for most commercial Web services development; Universal Discovery Description and Integration (UDDI); and Web services description language (WSDL). For each of these topics, the book offers a quick overview, Java tutorials with sample code, samples of the XML documents underlying the service, and explanations of freely-available Java APIs. Cerami also includes a guide to the state of Web Services, pointers to open-source tools and a comprehensive glossary of terms.