This monograph addresses four critical software development aspects for the engineering and execution of applications on parallel and Grid architectures.

A new directive-based language called ZEN is proposed for compact specification of wide value ranges of interest for arbitrary application parameters. The monograph contributes to various research areas related to integrated tool development for efficient engineering and high performance execution of scientific applications in Grid environments.

The ZEN Experiment Specification Language.- ZENTURIO Experiment Management Tool.- Tool Integration.- Optimisation Framework.- Scientific Grid Workflows.- Related Work.- Conclusions.