The scope of the present book may be gauged from the table of contents, it intended to provide basses of Electromagnetism Theorem: Classical and Relativistic for introductory course detail in the following concepts: History of electromagnetism, Charge and Coulomb Law, The Electric Field and Gauss's Law, Electric Potential, Capacitance and Capacitor, Current and Resistance. Direct-Current Circuits, advanced circuits, Magnetism and Its Historical Discoveries, Sources of Magnetic Fields, Electromagnetic Induction. Electromagnetic Waves, Alternating-Current Circuits, Relativistic Electromagnetism and applications of Electromagnetism Theorem.