Health care policy makers are facing the problem of limited expenditures and growing demand. Thus, quantitative approaches can help solve this urging issue. For this reason, the EURO Working Group on Operational Research Applied to Health Services (ORAHS) was formed in 1975. The objectives of the group are communication of ideas, knowledge and experience concerning the application of Operational Research approaches and methods to problems in the health services area, mutual assistance among members, co-operation on joint projects, inspiration with regard to approaches and attitudes in this field. The 27th meeting of this group was hosted by the University of Vienna, Austria, 2001. This book covers a selection of 18 papers presented at this conference.