Reality Subtext: The Rebecca Notebook reveals a lot of the inspiration for the story. Daphne coveted a mansion that became Manderley in her book. She later bought it when married, while worrying she wasn't adequate enough to be a wife for her fiance. Rebecca's affairs were drawn from the ones her father had, with her mother's only rule being that he needs to maintain discretion. Gerald du Maurier once broke that rule, causing a huge fight and near-scandal.
The novel plays a key role in Ken Follett's thriller The Key to Rebecca, in which it's used as a code book by a German spy ring operating in Cairo during World War II.
Taylor Swift based "tolerate it", the fifth track off her album evermore (2020), partially on Rebecca, stating that she could relate to the heroine's efforts to love and be loved by someone who is seemingly ambivalent to her.
I was thinking, "Wow, her husband just tolerates her." She's doing all these things and she's trying so hard and she's trying to impress him, and he's just tolerating her the whole time.
Technology Marches On: Rebecca apparently claimed that if she had a child, Maxim couldn't prove that he was the father and would be forced to raise the child as his. Daddy DNA Test is now a thing, so he would have been able to call her bluff. She wasn't even pregnant, but she wouldn't be able to use that excuse.
The 1939 stage play
Self-Adaptation: The book's author, Daphne DuMaurier wrote this play.
The musical
Cut Song: In many versions "Wir sind britisch" is removed and replaced with "Merkwürdig".
Troubled Production: The now-cancelled Broadway production, as detailed here and here. After a successful run in continental Europe, producer Ben Sprecher cancelled the London production as, partly due to an ancient stream found under the theater hampering the creation of a trapdoor for the staircase set piece, it became too costly. Even so, he decided it was ready for Broadway. A mysterious British investor, supposedly named "Paul Abrams", then put $4.5 million into the play... more than 10 times what the biggest-rolling investors usually throw into a Broadway musical, even one that's been wildly successful in London. But no one had ever heard of Abrams, and the producers later claimed they never met him in person. In September 2012, Abrams supposedly died of malaria. Yet there had been no obituaries for a wealthy man who died of malaria in the British newspapers, and no death certificates listed malaria as a cause. A spokesman for the estate refused to take phone calls, and used an email address that had been created a month earlier. Sprecher (who had never been lead producer on a Broadway musical) had already built the sets, so he lost millions when the production was cancelled the following month. The FBI arrested a stockbroker on Long Island for his attempt to defraud the producers by fabricating the foreign investors who were prepared to put the $4.5 million in. Things got worse when Rebecca’s publicist, Marc Thibedeau, was found to have been emailing future investors and advising them not to invest in in the show, having caught on that Abrams wasn’t a real person.
and here