The all pervasive web is influencing all aspects of human endeavour. In order to strengthen the description of web resources, so that they are more meaningful to both humans and machines, web semantics have been proposed. These allow better annotation, understanding, search, interpretation and composition of these - sources. The growing importance of these has brought about a great increase in research into these issues. We propose a series of books that will address key issues in web semantics on an annual basis. This book series can be considered as an extended journal published annually. The series will combine theoretical results, standards, and their realizations in applications and implementations. The series is titled βAdvances in Web Sem- ticsβ and will be published periodically by Springer to promote emerging Semantic Web technologies. It will contain the cream of the collective contribution of the Int- national Federation for Information Processing (IFIP) Web Semantics Working Group; WG 2. 12 & WG 12. 4. This book, addressing the current state of the art, is the first in the series. In subsequent years, books will address a particular theme, topic or issue where the greatest advances are being made. Examples of such topics include: (i) process semantics, (ii) web services, (iii) ontologies, (iv) workflows, (v) trust and reputation, (vi) web applications, etc. Periodically, perhaps every five years, there will be a scene-setting state of the art volume.