What do Hedy Lamarr, avant-garde composer George Antheil, and your cell phone have in common? The answer is spread-spectrum radio: a revolutionary invention based on the rapid switching of communications signals among a spread of different frequencies. Without this technology, we would not have the digital comforts that we take for granted today. Only a writer of Richard Rhodes’s caliber could do justice to this remarkable story. Unhappily married to a Nazi arms dealer, Lamarr fled to America at the start of World War II; she brought with her not only her theatrical talent but also a gift for technical innovation. An introduction to Antheil at a Hollywood dinner table culminated in a U.S. patent for a jam- proof radio guidance system for torpedoes—the unlikely duo’s gift to the U.S. war effort. What other book brings together 1920s Paris, player pianos, Nazi weaponry, and digital wireless into one satisfying whole? In its juxtaposition of Hollywood glamour with the reality of a brutal war, Hedy’s Folly is a riveting book about unlikely amateur inventors collaborating to change the world.