Helen Gurley Brown's self-help best-seller was the nominal source for this Hollywood sex romp, directed by Richard Quine, co-scripted by Joseph Heller and David R. Schwartz, and starring Tony Curtis and Natalie Wood.
Tony Curtis plays Bob Weston, a writer for the scandal sheet Dirt, who is working on an article on research psychologist Helen Gurley Brown (Natalie Wood) and her best-selling book Sex and the Single Girl. Bob needs to interview Helen, but she refuses to see him.
Bob impersonates one of her neighbors, Frank Broderick (Henry Fonda), as a ruse in order to see her on the pretext of marital counseling. After several meetings, Bob attempts to seduce her; after they fall out of a boat and head back to Helen's apartment to dry out, Bob plies her with martinis. Rip-roarin' drunk, Helen confesses her love for Bob.
He assures her it's fine, since he's not legally married, but Helen doesn't believe him and asks to meet his wife, Sylvia (Lauren Bacall). To fill up the breach, Bob mistakenly sends both his secretary, Susan (Leslie Parrish), and his ex-girlfriend Gretchen (Fran Jeffries) to see Helen -- both impersonating Sylvia.
When the real Sylvia arrives at Helen's apartment with the two other women, Sylvia has her hapless husband Frank put in jail for bigamy. By this point, Helen has realized Bob's skullduggery and leaves town with her colleague Rudy DeMeyer (Mel Ferrer).
Bob chases Helen onto the San Diego Freeway, where they also encounter Frank, who is being followed in a cab by Sylvia. A wild chase ensues as the bickering couples try to make it to their flights at the L.A. airport.