Lectures on Electromagnetic Field Theory: A Comprehensive Overview is for entry-level graduate students in electrical and computer engineering who want to have a comprehensive understanding of electromagnetic theory and its practical applications. This textbook covers topics from classical to quantum electromagnetics, as well as topics over a wide-frequency range, which can be applied from statics to extreme ultraviolet. The emphasis is on inculcating a physical and intuitive understanding of electromagnetics. The first part of the book covers the fundamentals, including constitutive relations, Green's function, boundary conditions, Poynting's theorem, gyrotropic media, and other important principles and theorems. The second part covers transmission lines, layered media, wave guidance, and resonance phenomena, including cavity quality factor. Homomorphism is used to connect layered media with transmission lines. The third part covers radiation by Hertzian dipole, antenna arrays, high frequency approximations, Sommerfeld integrals, and computational electromagnetics (CEM). This section introduces the rudiments of important concepts in CEM, including method of moments, finite element, and finite difference methods. The book ends by bridging the gap between classical and quantum by introducing students to quantum electromagnetics. This volume includes practical examples throughout and provides practice exercises to complement the individual chapter material.