This book constitutes the thoroughly refereed post-proceedings of the 6th International Conference on Parallel Processing and Applied Mathematics, PPAM 2005. The book presents 135 papers organized in topical sections on parallel and distributed architectures, parallel and distributed non-numerical algorithms, performance analysis, prediction and optimization, grid programming, tools and environments for clusters and grids, applications of parallel/distributed/grid computing, evolutionary computing with applications, parallel data mining, parallel numerics, and mathematical and computing methods.