Feedback Directed Optimization Chun Wai Liew HPCD-TR-13, CAP-TR-23 Optimization is a very important part of the design process. There are few design problems where concerns for either cost, quality, design time, etc., are not important. A great deal of time and design effort is spent on determining how to generate a solution that is optimized for a particular set of criteria, e.g., cost or time. However, optimization remains an ill-understood part of the process in many design problems. This thesis describes an innovative approach towards finding good solutions, i.e., optimized solutions, by using information about interactions between components (local interactions) gleaned from earlier solutions. The approach is called Feedback Directed Optimization (FDO). FDO is an iterative design approach based on the assumption that information about local interactions between solution components are essential towards being able to converge on good solutions to resource optimization problems. The approach includes techniques for (1) credit-blame assignment to determine where local interactions occur that might have been overlooked by the problem solver (2) controlling the problem solver on subsequent iterations to generate better solutions. These techniques have been developed and tested on several problem solvers in multiple domains. In addition, we have analysed the approach and have developed a prescriptive framework whereby new and existing problem solvers can use our techniques.