This book draws together the essential elements of classical electrodynamics, surface wave physics, plasmonic materials, and circuit theory of electrical engineering to provide insight into the essential physics of nanoscale light-matter interaction and to provide design methodology for practical nanoscale plasmonic devices. A chapter on classical and quantal radiation also highlights the similarities (and differences) between the classical fields of Maxwellsequations and the wave functions of Schrödingers equation. The aim of this chapter is to provide a semiclassical picture of atomic absorption and emission of radiation, lending credence and physical plausibility to the rules of standard wave-mechanical calculations. The structure of the book is designed around five principal chapters, but many of the chapters have extensive complements that either treat important digressions from the main body or penetrate deeper into some fundamental issue. Furthermore, at the end of the book are several appendices to provide readers with a convenient reference for frequently-occurring special functions and explanations of the analytical tools, such as vector calculus and phasors, needed to express important results inelectromagnetics and waveguide theory.