This book presents the state of the art in high performance computing and simulation on modern supercomputer architectures. It covers trends in hardware and software development in general and specifically the future of vector-based systems and heterogeneous architectures. The application contributions cover computational fluid dynamics, material science, medical applications and climate research. Innovative fields like coupled multi-physics or multi-scale simulations are presented. All papers were chosen from presentations given at the 11th Teraflop Workshop held in October 2009 at Tohoku University, Japan, and the 12th Teraflop Workshop held in March 2010 at the Hochstleistungsrechenzentrum Stuttgart (HLRS), Germany