This book constitutes the thoroughly refereed post-proceedings of the 7th International Conference on High Performance Computing for Computational Science, VECPAR 2006, held in Rio de Janeiro, Brazil, in June 2006.The 44 revised full papers presented together with one invited paper and 12 revised workshop papers were carefully selected during two rounds of reviewing and improvement for inclusion in the book. The papers are organized in topical sections on Grid computing, cluster computing, numerical methods, large-scale simulations in Physics, and computing in Biosciences. In addition, the book includes some of the presentations of the two associated workshops on Computational Grids and Clusters, and on High Performance Data Management in Grid Environments.