So this question's been festering in my head recently... After the Joker's accident with the chemicals, and he washed up miraculously alive and mentally broken, how did he become the criminally insane mastermind that he is? Did anything from his past have any fallout? Was his memory just wiped clean or distorted beyond his ability to decipher? What made him so special and not just some lunatic giggling in the corner of a cell at Arkham? Where did his criminal career start out that put him at Batman's level after the circumstances that made him the way he was?
Has any of this ever been explained in detail, besides maybe his very first appearance?