James Clerk Maxwell formulated in 1865 the great unification of the 19th century: electricity, magnetism, and light as manifestations of a single electromagnetic field governed by four equations. The work turns Faraday's experimental legacy — who thought in terms of lines of force but not equations — into a theory of enormous predictive power. Maxwell predicted the existence of electromagnetic waves traveling at the speed of light; Hertz verified them experimentally twenty-two years later. Without Maxwell there is no Hertz, without Hertz no radio, without radio no modern electronics. Einstein, in formulating special relativity, described Maxwell's equations as the starting point of his thinking.