Bombshell: The Hedy Lamarr Story profiles one of the most glamorous stars of Hollywood’s golden age, but it’s not your usual silver-screen documentary. Drawing on several books (most notably Hedy’s Folly by science writer Richard Rhodes), writer-director Alexandra Dean moves past Lamarr’s movie career in the 1930s and ’40s to explore her little-known sideline as an inventor, one whose patented device for radio “frequency hopping,” developed to guide torpedoes during World War II, has become a building block of modern wireless technology. Lamarr, who died in 2000, tells her own story on the soundtrack from a 1990 telephone interview with Forbes writer Fleming Meeks; in her proud, Austrian-accented English, she presents herself as a captive of her own beauty, still wondering what might have been had the world recognized her mind as much as her body.

Ironically, the device wasn’t much different from the music box Lamarr had torn apart as a child or the player-piano rolls Antheil had manipulated as an avant-garde musician. Like a piano roll, the machine they presented to the National Inventors Council used a ribbon with punched holes to manipulate a radio signal, bumping it from one frequency to the next; the torpedo would carry a similar device synchronized with the transmitter, so that the guidance signal might jump around the radio dial and elude German surveillance. Lamarr and Antheil won a patent for their system, though the U.S. Navy rejected it, arguing that the device would weigh down the torpedoes. According to Rhodes in Bombshell, the navy told Lamarr to stop wasting her time on inventions and instead use her celebrity to sell war bonds (which she did, to the tune of $25 million). Another interview subject, film historian Jeanine Basinger, sums up the prevailing ethos: “You don’t get to be Hedy Lamarr and smart.”

Jane ★★★ Directed by Brett Morgen. PG, 90 min. Fri 1/19-Thu 2/1. Gene Siskel Film Center, 164 N. State, 312-846-2800, siskelfilmcenter.org, $11.