This book focuses on the evaluation of the World Bank performance in delivering development aid to the Least Developed Countries. For this purpose, an extensive research is performed to analyze a set of 790 Implementation Completion and Results reports for key economic and financial indicators. Results of this research provide various insights into the appraisal and result stages of project delivery in the Least Developed Countries. In the final part of this analysis the minimum Social Return on Investment of the Least Developed Countries including all project costs is calculated. The outcome of the Social Return on Investment ratio indicates that projects delivered by the World Bank have a positive effect on the poor countries.