Convective fluid flow and convective heat transfer have many applications in various fields of science and engineering involving mechanical and chemical engineering, water resources engineering, geomechanics, environmental science, bio engineering, petroleum industry, material science and more to mention. The improvement in heat and mass transfer characteristics of a system can lead to the increase in irreversibilities and destruction of exergy. To overcome this conflict, the entropy generation minimization has been introduced and has received a great deal of attention in order to find the optimal working condition of a system because entropy generation is the measure of destruction of available work of the system. The main focus of this book is to investigate entropy generation in convective fluid flow in porous medium and nanofluid convection.