This chapter introduces the pivotal concept of electromagnetic induction, building upon the established relationship between electricity and magnetism. It begins by detailing experimental observations of induced currents in the presence of changing magnetic fields or relative motion between circuits and magnetic fields. The core of the chapter is Faraday’s law of induction, which quantitatively describes the electromotive force (emf) induced in a circuit as the negative time rate of change of the magnetic flux through the circuit. The chapter meticulously derives Faraday’s law for both moving circuits in static magnetic fields (motional emf) and stationary circuits in time-varying magnetic fields (transformer emf), unifying these phenomena into a general formulation. The differential form of Faraday’s law ( \(\mathbf {\nabla }\times \textbf{E} = -\partial \textbf{B}/\partial t\) ) is presented as a fundamental Maxwell’s equation, highlighting the non-conservative nature of the electric field in time-varying scenarios. Applications like Foucault currents (eddy currents) and the Kelvin effect (skin depth) are discussed, along with the unique inductive properties of superconductors (Meissner effect). The chapter then introduces inductance, a crucial property of circuits that quantifies their ability to oppose changes in current. Both self-inductance (due to the varying current within the circuit itself) and mutual inductance (magnetic coupling between circuits) are defined, with Neumann’s formula for mutual inductance. The energy stored in an inductor is derived, leading to the concept of magnetic energy density in space. Finally, the chapter presents magnetic potential energy for current-carrying loops in external magnetic fields, providing a framework for calculating forces and torques on such circuits. It introduces the concepts of Helmholtz free energy and Gibbs free energy for systems of conductors and magnetic media, demonstrating how these thermodynamic potentials can be used to analyze equilibrium states and derive forces and torques while maintaining constant fluxes or currents, respectively.