James Clerk Maxwell (1831-1879) was a Scottish physicist in the 19th century, who codified earlier work in electricity and magnetism by Michael Faraday, Andre Marie Ampere, and others into a linked set of four differential equations, known collectively as Maxwell's Laws or Maxwell's equations. Maxwell's Laws describe the nature of static and moving electric and magnetic charges, and the relationship between the two, namely, electromagnetic induction. The equations allow for the existence of a self-propogating electromagnetic wave which has the same velocity as that of light, suggesting that light is in fact that electromagnetic wave. The validity of that suggestion was later demonstrated in experiments by Heinrich Rudolf Hertz, and was elementary for the invention of radio, usually attributed to Guglielmo Marconi.
See also physics.