The nineteenth century was a formative period for electromagnetism and electrodynamics. Hans Christian Orsted's groundbreaking discovery of the interaction between electricity and magnetism in 1820 inspired a wave of research, led to the science of electrodynamics, and resulted in the development of electromagnetic theory. Remarkably, in response, Andre-Marie Ampere and Michael Faraday developed two incompatible, competing theories. Although their approaches and conceptual frameworks were fundamentally different, together their work launched a technological revolution--laying the foundation...