One day in 1960 something happened that seemed almost magical to many people. Dr. Theodore Maiman put into operation a device that gave off a thin, bright red beam of light. This remarkable device was the world's first laser. It was called a ruby laser because Maiman passed ordinary light through a ruby to produce the laser light. Since that day hundreds of different kinds of lasers have been made, and thousands of practical uses have been found for these modern "supertools."

Until the invention of the laser, using powerful beams of light was an idea that appeared mainly in science fiction. The first important example was in H.G. Wells's classic The War of the Worlds (published in 1898). In the novel sinister Martians use a terrifying heat ray to attack the earth. Later, in...