Cambridge University Press is now offering this well-known undergraduate electrodynamics textbook in a more reasonably priced printing. The Fourth Edition gives a solid foundation for investigating related applications (such as AC circuits, antennas, transmission lines, plasmas, optics, and more) and presents a rigorous, clear, and approachable study of the principles of electromagnetic theory. This textbook, which was written with undergraduate students' conceptual challenges in mind, uses thoughtful visuals and well-selected examples to demonstrate the theoretical concepts. It includes many problems, ranging from simple to complex, so that students can be assigned some to boost their confidence and others to stretch their wits. It strikes a balance between text and equations, allowing the physics to come through without sacrificing the rigor of the math.