Thisstate-of-the-artsurveyoftechnologies,algorithms,models,andexperiments in the area of Internet Quality of Service is the ?nal report of COST (European Cooperation in the ?eld of Scienti?c and Technical Research) Action 263,Qu- ity of future Internet Services, http://www. fokus. fraunhofer. de/cost263 (QofIS). COST 263 ran from January 1999 until October 2003 with the participation of some 70 researchers from 38 organizations from 14 European countries (France, Hungary, Italy, Sweden, UK, Belgium, Germany, the Netherlands, Portugal, Slovenia, Switzerland, Finland, Greece, Romania, and Spain). The Action - longed to the COST area ¿Multimedia and Internet Communication¿; together with COST 264, Networked Group Communication, this Action continued the e?ort started in 1992 by COST 237, Multimedia Telecommunications Services. Both groups have combined their e?orts now in the Network of Excellence in Emerging Networking Experiments and Technologies, http://www. ist-e-next. net (E-NEXT) of the 6th European Framework program. The book consists of seven chapters that were written in 18 months by 67 individual authors. The main objective of this book is to report the state of the art in the area of QofIS, as percieved by the authors, including achievements that wereoriginatedby the authors. The book wasdesigned in a top-downm- ner: after three years of running the Action with close co-ordination of research e?orts, it was easy to achieve a consensus on the table of contents. To ensure the content quality the following roles were de?ned and assigned to COST 263 members: chapter editor, chapter author, chapter reader.