Since I only recently started reading comic books on a regular basis, this question has only recently crawled into my brain
Hush and Ra’s al-Ghul seem to have displaced the Joker as Top Threat to the Batman’s Well Being. Both of them know that Bruce Wayne is the Batman IRL. So far, they both seem to be keeping the secret to themselves, but that could change.
What other comic-book type heroes have dangerous enemies who know what they do on their day jobs? Does Lex Luthor know that Superman is Clark Kent, Mild-Mannered Reporter for the Daily Planet? What about Spider-Man? Any of his favorite arch-villians know he’s really Peter Parker?
And while we’re on the subject, in the canonical DC stories, does Jim Gordon know that Bruce Wayne is really the Batman?
In an early post-Crisis issue of Superman, Luthor commissioned one of his minions to find out everything she could about Superman. She figured out that Kent and Superman were one and the same but Luthor flatly refused to believe that anyone with the power of Superman would pretend to be anyone other than Superman.
I thought she just entered all the information about Superman into a computer, which came to the conclusion that Supes was Clark Kent. Luthor laughed at the idea, and then fired her. I remember it as the comic with a large computer screen saying Clark Kent is Superman on the cover.
Oh, Mr Myxlplixt (Sp?) knows, but he’s practically a god, so he doesn’t count.
Anyway, I’m pretty sure Kraven knows Spidey’s ID. There’s also Puma. Green Goblins 1 and 2 know. Venom knows, but I don’t think Carnage knows. Black Cat knows, but she’s not a villian anymore. Not sure if Doc Ock knows in the canon comics. There’s probably a few more, plus a whole bunch of allies.
It’s been a while since I’ve seen much interaction with Gordon and Batman - we were, as I recall, sometimes given hints that he knew, but there was never any confirmation that I saw.
I seem to recall vaguely that it has been implied that the Joker, too, is aware of Batman’s dual identity.
Lex Luthor seems to be aware of Batman’s ID as well, according to events in Superman/Batman’s first arc. Master assassin Cain is aware of Bruce/Batman.
This is one of the more obvious ones, so I’m surprised I got to it first.
The Kingpin has known of Daredevil’s secret identity for a long time, and did his best to destroy Matt Murdock’s life as a result (got him disbarred, blew up his house I think?). Karen Page sold him Matt’s secret back when she was a addict.
Waaay back in the day, Doctor Octopus captured Spider-Man when he was weakened and unmasked him in front of witnesses. Because of Spider-Man’s poor performance during the fight neither Doctor Octopus nor the witnesses believed that Peter was really Spider-Man.
Many issues later, again while weakened and feverish, Peter revealed his dual ID to Gwen Stacy and her father, but then got The Prowler to impersonate Spider-Man to cover.
Professor Zoom and Abracadabra both knew Barry Allen was the Flash. They were from the future and it was a part of history books and biographies.
Killer Moth did learn Batman’s secret identity. But a brain injury has blocked the memory.
Hugo Strange learned Batman’s secret identity and was going to sell it to the highest bidder. IIRC The Joker killed Strange to prevent this. ‘Nobody knows my secret identity! Nobody can know Bat’s identity either.’
There was another issue of The Flash with a woman who had an obsessive crush on him mentally compelled Flash to come to her hotel room. After sizing him up (in fairly overtly sexual terms for a comic book in the 70s) she forced him to remove his mask. She was very disappointed that he was so orcinary looking.
I’m not sure what the current canon is regarding Superboy, I never quite worked out where he fitted in post-crisis with the Legion still operating. But one of kids Clark went to school with knew he was Superboy, although Clark didn’t know he knew.
I remember that one, so it must have been early 80s rather than 70s. Like you I was quite surprised at the sexual aspect from a mainstream comic of the era. It was made even more surpising when it was revealed that the ‘woman’ was only about 16 years old.
Current canon is that Clark was never Superboy. First, a ‘pocket universe’ was created to explain his presence in the Legion, then his important acts in the Legion were eventually shifted to Mon-El/Lar Gand/Valor (And Supergirl to Laurel Gand). And post Zero-Hour canon has been simplified greatly.
In current canon, then only Superboy to have existed is Kon-El/Connor. (Who is a semi-clone of Superman, with human DNA from either the head of Project Cadmus or Lex Luthor…)
