Land use is changing all over the world with the passing of time. Obviously there are some causes of changing land use patterns. In the context of Bangladesh, a highly populated country in the world, using of cropland as fish farming is expanding over time because of market demand, and the favorable growth rate of the fish price; in contrary, uncertainty of rice production and low market price of rice also enhances the process. Notwithstanding, most farmers try to secure rice supply for their own consumption. This book provides an overview of how various factors interact in particular contexts to identify the causes of land use change, and how the farmer allocates physical resources optimally to maximize farm profit under different economic limitations. A good understanding of influencing factors and thee optimal use of given physical resources would help the policy makers to draw up new public land use policies.