In this book, Jos de Bruijn and his coauthors lay the groundwork for understanding the requirements that form a picture of various aspects related to Semantic Web services, such as static background knowledge in the form of ontology, the functional description of the service, and descriptions of service behavior. They introduced the Web Service Modeling Language (WSML), which provides the means to describe the function and behavior of Web services, as well as the underlying business knowledge, in the form of ontology, the conceptual foundation of the Web Service Modeling Ontology. Academic and industrial researchers and professionals will find a comprehensive picture of the concepts and challenges in the field of Semantic Web services, Web Services Modeling Language and its relationship with the Web Services Modeling Ontology, and in-depth treatment of both enabling technologies and theoretical foundations.