Patent No. 174,465 for "improvements in telegraphy"-the telephone-often is called the most valuable patent ever issued. After experimenting with various acoustic devices, Alexander Graham Bell produced the first intelligible electronic transmission with a message to his assistant, Thomas Watson, in the next room of their Boston lab: "Mr. Watson, come here. I want to see you."

Bell attended the Royal High School in Edinburgh before going to study at Edinburgh University. In 1870 his parents decided to move to Ontario, Canada, when doctors suggested the change of climate might provide a cure for his ill health. In 1871 Bell went to the United States, where he became a professor of vocal physiology in Boston. The Scot immigrant was 29 years old at the time, earning his living as a teacher of deaf children. Both his mother and his wife had hearing impairments. One of his most famous students was Helen Keller, the brilliant blind and deaf author.

In addition to the telephone, Bell held patents for the telegraph, photophone, phonograph, hydrofoils, and a selenium cell. Bell experimented with fax machines and with an early form of fiber optics. He developed helicopter design and X-ray photography. In the early 1890s, Bell conducted aviation experiments and ran the National Geographic magazine. In 1898, Congress appointed him as a Smithsonian regent.

After his son Edward died in childbirth of a collapsed lung, Bell toiled in his lab to develop a respirator apparatus that would help people breathe. His "vacuum jacket" was more than 40 years ahead of the iron lung. And when President Garfield was shot and physicians were trying to locate bullets, Bell invented the metal detector, too late to save the president.