On twin worlds separated by scant vibration frequencies, there were many parallels among their peoples. This included the Doctors Bradford Thorne, each of whom were renowned surgeons of Gotham City with a curious addiction... to crime! As the Crime Doctors, both men twice matched wits with the Darknight Detectives, the Batmen, using tools such as their head reflectors and medicinal bag of gimmicks.
While the Earth-One Thorne crossed passes with the conniving Sterlng Silversmith, the Earth-Two version dealt with more common crooks. Both men not only treated the underworld by means of their "Crime Clinics" but also participated in felonies themselves. Although it was simply for the thrill, not for the money. On the second battles with the Doctors, the Batmen found these threats eliminated. For the Earth-One Doctor, this occured when Bradford sustained brain damage (which meant that Batman's secret identity, which Thorne had treated as Bruce Wayne and learned of in battle with the Caped Crusader, was preserved). For the Earth-Two Doctor, this occured when Thorne was shot by one of his henchmen for not having saved his wife. However, during the Crisis on Infinite Earths, the modern Crime Doctor would return... whether he had recovered from his head trauma or had been plucked from another time period is unknown. Regardless, that was his final appearance.