During the duration of the Batman TV series and several years afterward into the early 1970s the Batman was considered little more than pop culture joke.
Several writers and artists attempted to bring the 'dark' back to the Dark Knight with limited success.Even Batman's once notorious 'Rogue's Gallery' of villains were little more than pathetic parodies of their once former villainous selves.
One of the artists who slowly and meticulously brought Batman back to his dark roots was Neal Adams.
His stellar work on DC Comics' Brave And The Bold titles. which teamed Batman with various DC heroes. garnered praise from fans.
His depiction of Batman reestablished Batman as 'The World's Greatest Detective' and 'Dark Knight'.
Adams drew Batman as a dark mysterious figure, often cloaked in shadow, who was a master of multiple forms of combat and possessed an analytical and logical mind that rivaled Sherlock Holmes.
Successive stories cemented Batman's transformation. But one thing was missing.
Batman's arch nemesis: The Joker, was stilled depicted as nothing more than a bumbling, comical 'Clown of Crime'. That is until writer Denny O'Neil and artist Neal Adams reintroduced him in Batman #251.
In that landmark issue the Joker was transformed back to his original maniacal, madman persona as he was originally presented when he was first created.
Literally insane, the Joker was portrayed as a ruthless, blood-thirsty killer with no regard for human life, an ego-maniac and the polar opposite of Batman.
The concept that the Joker could not exist without the Batman and Batman without the Joker persists to this day.
In this ground-breaking story the Joker meticulously eliminated former members of his gang whom he believed let him down or betrayed him.
In a desperate race against time Batman finds himself one step behind the Joker ultimately resulting in a near fatal final meeting with the mad menace.
Many credit this issue ushering in the new 'dark' era of the Batman and elevating the Joker to the head of the list of classic villains.