The authors have detailed a comprehensive history of GAEC, its mission and its impact so far on the peaceful applications of nuclear techniques in Ghana. The book has also attempted to explain reactor engineering in layman’s language, such that the average reader could comprehend how a nuclear reactor works – the structure and functions of the various buildings comprising a reactor, the controls, the fuel assemblies and how the reactor goes critical for power to be produced and harnessed in the form of steam that is used to turn turbines to produce electricity.