Thepapersinthis volumewerepresentedatthe4thInternationalConferenceon Large-Scale Scienti?c Computations ICLSSC 2003. It was held in Sozopol, B- garia, June 4 8, 2003. The conference was organized and sponsored by the C- tral Laboratory for Parallel Processing at the Bulgarian Academy of Sciences. Support was also provided from the Center of Excellence BIS 21 (funded by the European Commission), SIAM and GAMM. A co-organizer of this tra- tional scienti?c meeting was the Division of Numerical Ana ...