The tutorial aims at providing a deep comprehension of the Web Service Composition problem and automated techniques to tackle it. Web Service Composition is currently one of the most hyped and addressed issue in the Service Oriented Computing. Starting from an analysis of current technologies and standards for Web Service Composition, the tutorial will lead the attendees to consider formal models at the base of current proposals, and techniques that can be fruitfully considered to address automatic composition synthesis in each of them. More in detail, attendees will consider: (i) basic technologies and standards for Web Service invocation and description (SOAP, UDDI, WSDL, ...); (ii) advanced technologies and standards for orchestration and inter-organizational process enactment, in particular WSBPEL and WS-CDL; (iii) models for Web Service composition; (iv) formal tools for both data-centric and process-centric synthesis, including query reformulation a?la Data Integration, transition-systems based formalisms, trace-based formalisms, logics of programs and processes. In particular, we will show how these formal tools can be applied for Automatic Web Service Composition; (v) current state-of-the-art research results in automatic service composition, drawing a comparison and defining a unifying framework.