Jacob Bear is Professor Emeritus in the Department of Civil Engineering at the Technion – Israel Institute of Technology, Haifa, Israel. He is one of the most influential scientists in the field of transport in porous media. His research has focused on many fundamental issues such as the derivation of the basic constitutive equations for flow and transport, and the development of the concept of the dispersivity tensor, and on their applications to solve practical problems, especially sea water intrusion in coastal aquifers. He is widely recognized as a pioneer in the field of groundwater hydraulics. Jacob Bear has also been an influential educator. He has taught in universities, delivered many short courses for engineers and scientists, and has written several major text books that have influenced generations of professionals all over the world.