The main topic of this book is Maxwell's Equations. These are a set of eight, scalar, first-order partial differential equations which constitute a complete description of classical electric and magnetic phenomena. To be more exact, Maxwell's equations constitute a complete description of the classical behavior of electric and magnetic fields.

Electric and magnetic fields were first introduced into electromagnetic theory merely as mathematical constructs designed to facilitate the calculation of the forces exerted between electric charges and between current carrying wires. However, physicists soon came to realize that the physical existence of these fields is key to making Classical Electromagnetism consistent with Einstein's Special Theory of Relativity. In fact, Classical Electromagnetism was the first example of a so-called field theory to be discovered in Physics. Other, subsequently discovered, field theories include General Relativity, Quantum Electrodynamics, and Quantum Chromodynamics.

At any given point in space, an electric or magnetic field possesses two properties a magnitude and a direction. In general, these properties vary (continuously) from point to point. It is conventional to represent such a field in terms of its components measured with respect to some conveniently chosen set of Cartesian axes (i.e., the standard x-, y-, and z-axes). Of course, the orientation of these axes is arbitrary. In other words, different observers may well choose differently aligned coordinate axes to describe the same field. Consequently, the same electric and magnetic fields may have different components according to different observers. It can...