0.1 Introduction The present volume is about the physics of electromagnetic scattering, not mathematics, and is intended as a reference book for engineering and physics students as well as researchers in electromagnetic scattering. Although the subject is on electromagnetic scattering, acoustic or scalar scattering will be discussed occasionally when it is deemed helpful and advantageous. In the current decade we are witnessing an emergence of inverse scattering theory. Before we embark on this exciting journey, perhaps this is an appropriate time to summarize and assess in one volume some of...