The EuroQol Group is an international, cross-disciplinary group set up in 1987 to investigate issues related to the valuation of health. This book presents a series of papers from the early 1990s that illustrate many key aspects of the development of EQ-5D including: the descriptive system, self-rated health, valuation issues, health status scaling, modeling and valuation, semantic issues, reliability, and comparison with other instruments. The book provides a detailed insight into the analytical processes involved in the development of the EQ-5D as one of the foremost instruments for the measurement and valuation of health-related quality of life, and will be of particular interest to researchers in this area. It will also appeal to all those involved in outcome measurement - clinical personnel, health policy advisers and administrators, those involved in audit and quality assurance, health economists, and the pharmaceutical industry.