Spoilers incoming for Batman #38, so if you haven't read it yet you've been warned.
Batman is investigating the newest victims of Victor Zsasz when he finds a letter the villain was sent while in prison. The letter is taken as a typical one sent to inmates explaining that they can repent their sins. Batman catches a few issues in the note though, including a reference to the Book of NED.
That happens to be part of an anadrome, which when read
O'Neil was one of the first Batman writers to really explore the inner workings of the Dark Knight, so much so that he theorized Bruce Wayne was the secret identity and not Batman. That logic has stuck a great deal since then, with many writers putting their own spin on that idea.
O'Neil also created iconic landmarks in Gotham like Arkham Asylum, as well as one of the Dark Knight's greatest villains Ra's Al Ghul. He also created Ra's League of Assassins and his daughter Talia Al Ghul.
You can see the image above.
Batman #38 is written by Tom King with pencils and inks by Travis Moore and colors by Giulia Brusco. The main cover is provided by Tim Sale and Dave Stewart and the variant cover is by Olivier Coipel.
“The Origin of Bruce Wayne! If Mattie could grow up to be anybody, he’d grow up millionaire playboy Bruce Wayne. But what would happen if he was forced to relive the worst tragedy of Bruce’s life and his parents were murdered? Batman’s hunt for the killer puts him face to face with a strange mirror version of his own past."
Batman #38 is in comic shops now.