This volume contains a selection of papers referring to lectures presented at the symposium "Operations Research 2004" (OR 2004) held at Tilburg University, September 1-3, 2004. This international conference took place under the auspices of the German Operations Research Society (GOR) and the Dutch Operations Research Society (NGB). The symposium had about 500 participants from more than 30 countries all over the world. It attracted academicians and practitioners working in various fields of Operations Research and provided them with the most recent ad vances in Operations Research and...