§15§This proceedings volume contains 6 invited state of the art lectures and 50 contributed papers presented at OR 98 held at the Swiss Federal Institute of Technology (ETH) Zurich, 31 August - 3 September 1998. This 4-annual international conference was jointly organized by the Swiss, German and Austrian OR-societies and co-sponsored by SIGOPT. The conference had 450 particpants from 36 countries around the world. The proceedings of this conference are subdivided according to the eleven sections of the conference, namely - Continuous Mathematical Optimization (8 papers), - Discrete Mathematical Optimization (12 papers), - Stochastic Modelling, Optimization 〓15§ 〓03§PrefaceOpening SessionPlenary LecturesSection 1 A: Mathematical Optimization - ContinousSection 1 B: Mathematical Optimization - DiscreteSection 2: Stochastic Modelling, Optimization & SimulationSection 3: Econometrics & StatisticsSection 4: Mathematical Economics, Game Theory & Decision TheorySection 5: Banking & FinanceSection 6: Operations & Production ManagementSection 7: Energy & EcologySection 8: TelecommunicationSection 9: Logistics & TransportationSection 10:Fuzzy Systems & Neural NetworksSpecial Section: GOR Diploma PrizeAuthor Index