This book presents thoroughly arranged tutorial papers corresponding to lectures given by leading researchers at the Second International Summer School on Reasoning Web in Lisbon, Portugal, in September 2006.

Building on the predessor school held in 2005 and published as LNCS 3564, the ten tutorial lectures presented provide competent coverage of current topics in semantic Web research and development. The lectures are organized in topical sections on semantic Web query languages; semantic Web rules and ontologies; bioinformatics and medical ontologies and industrial aspects.

The Semantic Web is a major endeavor aimed at enriching the existing Web withmetadataandprocessingmethodssoastoprovideWeb-basedsystemswith advanced(so-calledintelligent)capabilities, inparticularwithcontext-awareness and decision support. The advanced capabilities striven for in most Semantic Web application s- narios primarily call for reasoning. Reasoning capabilities are o?ered by exi- ing Semantic Web languages, such as BPEL4WS, BPML, ConsVISor, DAML-S, JTP, TRIPLE, and others. These languages, however, were developed mostly from functionality-centered (e.g., ontology reasoning or access validation) or application-centered (e.g., Web service retrieval and composition) perspectives. A perspective centered on the reasoning techniques (e.g., forward or backward chaining, tableau-like methods, constraint reasoning, etc.) complementing the above-mentioned activities appears desirable for Semantic Web systems and - plications. The workshop on Principles and Practice of Semantic Web Reas- ing, which took place on December 8, 2003, in Mumbai, India, was the ?rst of a series of scienti?c meetings devoted to such a perspective. JustasthecurrentWebisinherentlyheterogeneousindataformatsanddata semantics, the Semantic Web will be inherently heterogeneous in its reasoning forms.Indeed, anysingleformof reasoningturnsouttobeirrealin theSemantic Web. For example, ontology reasoning in general relies on monotonic negation (for the metadata often can be fully speci?ed), while databases, Web databases, and Web-based information systems call for non-monotonic reasoning (for one would not specify non-existing trains in a railway timetable); constraint reas- ing is needed when dealing with time (for time intervals have to be dealt with), while(forwardand/orbackward)chainingisthereasoningofchoicewhencoping with database-like views (for views, i.e., virtual data, can be derived from actual data using operations such as join and projections)."

This book constitutes the refereed proceedings of the 5th International Conference on Deductive and Object-Oriented Databases, DOOD'97, held in Montreux, Switzerland, in December 1997. The 22 revised full papers presented in this book were selected from a total of 59 submissions. Also included are abstracts or full versions of three invited talks and three tutorials and six short presentations. The papers are organized in topical sections on materialized view maintenance, extending DBMs features, database updates, managing change in object databases, semantics of active databases, formal semantics, and new directions.

The objective of this state-of-the-art survey is to give a coherentoverview of the main topics and results achieved by the Network of Excellence REWERSE on "Reasoning on the Web," funded by the European Commission and Switzerland within the "6th Framework Programme" (FP6), from 2004 to 2008.

The material has been organized into eight chapters, each of which addresses one of the main topics of REWERSE: hybrid reasoning with rules and ontologies, lessons in versatility or how query languages adapt to the Web, evolution and reactivity in the Semantic Web, rule-based policyrepresentations and reasoning, component models for Semantic Weblanguages, controlled English for reasoning on the Semantic Web, semantic search with GoPubMed, and information integration inbioinformatics with ontologies and standards.

Each chapter gives an in-depth coverage of the subject and provides an extensive bibliography with pointers to further literature.