Sedimentary rocks are created by the deposition or accumulation of material, organic particles, or minerals in bodies of water and formed at the Earth’s surface. Sedimentation is the name given to the formation of these rocks. Limestone, dolostone, clay, sandstone, sandstone, and shale are some common sedimentary rocks formed out of the sedimentation and cementation processes that cause these particles, which can be coarse, medium, or fine-grained or stratified according to their conditions of formation. The first section of this book discusses different aspects of sedimentary rocks. Aquifers are vital resources of freshwater in many countries. However, such groundwater resources are limited, scarce, and unevenly distributed over the Earth’s surface. The second section of this book discusses the basaltic aquifer and aquifers in South Africa.