Toward the end of the nineteenth century, a famous scientist is reputed to have expressed sympathy for his younger colleagues in physics. He said that all the great discoveries had already been made and that all physicists had to look forward to was calculating known answers to a precision of one or two more decimal points. He could not have been more wrong. Within a period of three decades, physics was to undergo one of the most dramatic revolutions in its history. The apparently solid, dependable classical physics--based on the mechanics of Isaac Newton and the electromagnetism of James Clerk Maxwell--were overthrown and replaced by an entirely new view of the world. One of the two cornerstones of this new world view was quantum theory.

The architect of this new view was the German physicist, Max Planck. The problem that led Planck to the quantum theory...