Agricultural, industrial, municipal, navigational, and recreational demand of water is met by two major sources surface water and groundwater. Compared to surface water sources which depend upon the annual rainfall and the melting of ice and snow, ground water supply is more reliable because it does not directly depend on the annual rainfall. Therefore utilization of groundwater resources is growing over the years. However unplanned use of groundwater has caused several problems in many places. Groundwater modeling is used as a major tool to understand the complex dynamic behaviour of aquifer system. This required aquifer system parameters which are very difficult to evaluate by field methods alone. Inverse modeling helps in adequate assessment of these parameters. These aspects for certain specific cases are dealt in the book involving modeling and inverse modeling in groundwater hydrology.