th This volume contains 40 contributed papers accepted for presentation at the 6 Annual European Symposium on Algorithms (ESA 98), Venice, Italy, August 24 26, 1998, and the invited lectures by Eli Upfal (Brown) and Je?rey Vitter (Duke). ESA is an annual meeting, with previous meetings held in Bad Honnef, Utrecht, Corfu, Barcelona, and Graz, and covers research in the use, design, and analysis of e?cient algorithms and data structures as it is carried out in computerscience, discreteappliedmathematicsandmathematicalprogramming. Proceedings of ESA have been traditionally part of the LNCS series of Springer- Verlag. The symposium is promoted and coordinated by a steering committee, whose current composition is: Gianfranco Bilardi, Padua & UIC Kurt Mehlhorn, Saarbrucken ] Josep Diaz, Barcelona Ralf H. M] ohring, Berlin Giuseppe F. Italiano, Venice Gerhard Woeginger, Graz The Program Committee of ESA 98 consisted of: Gianfranco Bilardi, Co-chair, Kurt Mehlhorn, Saarbrucken ] Padua & UIC Friedhelm Meyer auf der Heide, Jean Daniel Boissonnat, Paderborn Sophia Antipolis Grammati Pantziou, Patras Kieran T. Herley, Cork Mike Paterson, Warwick Dorit Hochbaum, Berkeley Jos e Rolim, Geneva Giuseppe F. Italiano, Co-Chair, Erik M. Schmidt, Aarhus Venice Maria Serna, Barcelona Lud? ek Ku? cera, Prague Paul Vitanyi, Amsterdam Richard J. Lipton, Princeton Gerhard Woeginger, Graz Yishay Mansour, Tel-Aviv There were 131 extended abstracts submitted in response to a call for - pers."

This book constitutes the refereed proceedings of the 4th International Symposium on Solving Irregularly Structured Problems in Parallel, IRREGULAR'97, held in Paderborn, Germany, in June 1997.
The 18 revised full papers presented were carefully selected by the program committee for inclusion in the volume; also included are full papers by the five invited speakers. Among the topics covered are discrete algorithms, randomized methods and approximation algorithms, implementations, programming environments, systems and applications, and scheduling and load balancing.