U.S. Patent No. 2, 292, 387 for a "Secret Communication System" was issued to Hedy Kiesler Markey and George Antheil in 1942. (Markey was the surname of a husband she had divorced in 1940.) The frequency-hopping technology was not put to use in World War II, but it was employed in 1962 during the blockade of Cuba.

WSJ: Book Review: Hedy's Folly

As you have said, in 1940 Hedy Lamar (Obituary, January 29th) and a film-score composer, George Antheil, developed the technology, then called spread spectrum.

ECONOMIST: Letters | The

As Mr. Rhodes relates, Hedy Lamarr was hardly an intellectual, but she was a indefatigable tinkerer.

WSJ: Book Review: Hedy's Folly