This free book is an excellent tutorial book for beginners. It is a collection of notes and sample codes written by the author while he was learning PHP himself. Topics include Service-Oriented Architecture (SOA), Web Services Definition Language (WSDL), Simple Object Access Protocol (SOAP), Universal Description, Discovery and Integration (UDDI), Data Model, Encoding, HTTP Binding, Message Exchange Patterns, Properties, RPC, Web Method. Key sections: - What Is a Web Service? - Web Service Related Technologies - What Is SOAP? - SOAP Communication Example - SOAP Message Structure - SOAP Fault Message - SOAP Protocol Binding - SOAP Distributed Processing Model - SOAP Features - SOAP Modules - What Is SOAP Data Model? - What Is SOAP Encoding? - Multiple References and Circular Referencces