Millions of radio listeners each day tune in their favorite FM (i.e., frequency modulation) stations to hear crystal clear, high-fidelity music and other programming. FM radio offers clarity and a dynamic range that cannot be matched by AM (i.e., amplitude modulation) broadcasting. Many people cannot explain how the signals reach their radios or why the FM stations sound so much better than their AM equivalents. However, if people enjoy the programming that FM stations provide, then they owe a debt of gratitude to the inventor of the technology that made it all possible: Edwin Howard Armstrong.

Armstrong was born on December 18, 1890, in New York City, the first child of Emily and John Armstrong. Young Edwin grew up in a family that was well to do, well educated, and a cornerstone of their Yonkers, New York, community. A quick mind was...