The Semantic Web aims at enriching the existing Web with meta-data and processing methods so as to provide web-based systems with advanced capabilities, in particular with context-awareness and decision support. The objective of this book is to provide a coherent introduction to semantic web methods and research issues with a particular emphasis on reasoning. The focus of this year's Summer School on 'Reasoning Web' focused on applications of semantic technologies in software engineering and the reasoning technologies appropriate for such an endeavor with an emphasis on description logics (DL) as reasoning formalisms for the Semantic Web, ontologies and domain specific languages as means for modeling, process semantics for process refinement and grounding as well as semantic query languages. The volume contains a collection of six thoroughly revised tutorial papers based on lectures given by leading researchers at the 6h International Summer School on the Reasoning Web, held in Dresden, Germany, from August 30 to September 3, 2010.