Climate change is a complex long term problem and two centuries in the making. There are only but few human activities that do not contribute to it. Climate change is altering the hydrologic cycle, thus affecting the hydrology and water resources of river basins. This study has been tailored to examine the present and future hydroclimatology of Lower Niger River basin, West Africa. Therefore, the chapters have been designed and developed in a systematic way. The text is arranged in six chapters. Chapter 1 beside introduction to the study discusses the climate-related problems of the Lower Niger Basin, the objective and justification of the study. As well as why the focus of the study is on water and operational definitions. The study draws from various literatures; the same have been discussed in chapter 2. Chapter3 introduces the study area, and discusses the hydrology, topography, weather and climate of the area. Also discussed, is the geology, soil, economic structure, population and settlement, energy and agricultural activities of the area and their interactions with climate. Chapters 4, 5 and 6 discuss the study approach, the results and conclusion respectively.