Short answers, pulled from the story.
Electromagnetism is the second strongest of the four fundamental forces of nature and acts as the invisible glue holding every atom together. It generates force fields through the dance of charged particles, creating electrostatic attraction between atomic nuclei and electrons that prevents matter from disintegrating.
Thales of Miletus discovered the properties of electricity and magnetism around 600 B.C.E. He observed that rubbing amber with cloth gave it the power to attract light objects and noted that magnetic rocks could attract one another.
Hans Christian Ørsted discovered that an electric current flowing through a wire caused a nearby compass needle to deflect in April 1820. This observation proved that electricity could generate a magnetic field and shattered the centuries-old belief that electricity and magnetism were separate forces.
James Clerk Maxwell published his Treatise on Electricity and Magnetism in 1873. His equations provided a complete mathematical description of classical electromagnetic fields and unified electricity and magnetism into a single force.
Quantum electrodynamics or QED is a theory that modified Maxwell's equations to describe the electromagnetic field in terms of discrete particles called photons. It explains how changes in the electromagnetic field are expressed as discrete excitations to allow for precise understanding of interactions at the subatomic level.