In 1989 Stuart Parkin discovered the phenomenon of oscillatory interlayer coupling in magnetic multilayers, by which magnetic layers are magnetically coupled via an intervening non-magnetic metallic spacer layer. Parkin found that the sign of the exchange coupling oscillates from ferromagnetic to antiferromagnetic with an oscillation period of just a few atomic layers. Remarkably, Parkin discovered this phenomenon in thin film magnetic heterostructures that he prepared in a simple home-made sputtering system. Parkin, moreover, showed that this phenomenon is displayed by almost all metalllic transition elements. In what is often referred to as "Parkin's Periodic Table", Parkin showed that the strength of this oscillatory interlayer exchange interaction varied systematically across the Periodic Table of the elements. Parkin made numerous other fundamental discoveries which continued the development of the field of "spintronics" of which he is recognised as a prolific scientist.