James Clerk Maxwell is the one theoretical physicist between Isaac Newton and Albert Einstein of a stature comparable to theirs. Maxwell's contributions to science ranged over many areas, of which the two greatest were his creation of the electromagnetic theory of light, and his work on molecular physics, gas theory, and statistical mechanics. He entered the scientific scene in the early 1850s, immediately after the principle of conservation of energy had been established. Its impact is seen everywhere in his work.

A descendant of a distinguished Scottish family, the Clerks of Penicuik, and, by an illegitimate line, of the ninth Lord Maxwell, he was born in Edinburgh but lived much of his life at his estate in Galloway in southwest Scotland, where he inherited 2,000 acres of rich farmland. From the ages of ten to nineteen he was educated in Edinburgh, entering the...