Inverse methods have become a funda~ental tool in the physical sciences for remote sensing of unknown objects and reconstructing the physical properties. A Special Issue of the IEEE Transactions on Antennas and Propagation intends to provide an overview of this iuportant emerGing discipline and to provide examples of the wide scope of methods used to investigate inverse problems in electromagnetics, ranging from purely theoretical considerations to some very practical problems. In this article we would like to give a qualitative introduction to electromagnetic inverse scattering. Instead of surveying the many diverse applications of inverse methods, we shall concentrate on the examples which illustrate the fundamentals of inverse scattering and which have been studied at the Naval Research Laboratory (NRL).