It's kind of prophetic that back in August of 1942 (Detective Comics #66) that the doctor who was either Harvey Dent's psychiatrist/or the surgeon who could have repaired Two-Face's facial deformity is named "Dr. Ekhart."
I just read that issue in a TPB collection from the library, and I own an earlier collection that also contains it. Dr. Ekhart was a "European specialist," the only plastic surgeon skilled enough to repair the facial scarring that Harvey "Kent" (as he was originally known) had sustained. Unfortunately, Dr. Ekhart had gone to visit his brother in Germany some time back, and was apparently Jewish or gay or something, since he'd been arrested by the Nazis and imprisoned in a concentration camp. So basically Hitler was indirectly responsible for Harvey's turn to madness and crime.
When Two-Face returned a year later in
Detective #80, it turned out that Ekhart had escaped from the concentration camp and was able to repair Harvey's face, so he gave up his life of crime and was reunited with his fiancee Gilda. After a false alarm in a 1952 story (in which the apparent Two-Face was an impostor), Harvey was scarred again in an explosion while attempting to stop a robbery (what are the odds?), and returned to his criminal ways. Except his career was cut short soon thereafter by Dr. Wertham and the Comics Code, with his grisly and un-kid-friendly visage being banned from the comics and not appearing again until Denny O'Neil brought him back in 1971. (Which is why Two-Face never appeared in the Adam West series. Which is a shame, since his obsession with duality would've been a perfect gimmick for that show.)