The Web services architecture offers a new way to think about and implement application-to-application integration and interoperability that makes the development platform irrelevant. Two applications, regardless of operating system, programming language, or any other technical implementation detail, communicate using XML messages over open Internet protocols such as HTTP or SMTP. The Simple Open Access Protocol (SOAP) is a specification that details how to encode that information and has become the messaging protocol of choice for Web services. This is a detailed guide to using SOAP and other Web services standards - WSDL (Web Service Description Language), and UDDI (Universal Description, Discovery, and Integration protocol). It covers the concepts of the Web services architecture and offers practical advice on building and deploying Web services in the enterprise. It decodes the standards, explaining the concepts and implementation in a clear, concise style. You'll also learn about the major toolkits for building and deploying Web services. Examples in Java, Perl, C#, and Visual Basic illustrate the principles. Significant applications developed using Java and Perl on the Apache Tomcat Web platform address real issues such as security, debugging, and interoperability.