Kicked out of a university for his unorthodox teaching methods, Professor Jonathan Crane now dresses symbolically as a scarecrow, and employs a fear toxin that causes its victims to hallucinate the presence of what they most fear.

Dick Grayson first appeared in Detective Comics #38 in April 1940 as Robin the Boy Wonder. He would later take other superhero names including Nightwing and Agent 37.

Adam West is best known for the title role in the 1960s ABC series Batman.

Ra's al Ghul first appeared in Batman #232. His name in Arabic translates to "The Demon's Head".

Commissioner James Gordon debuted in the first panel of Detective Comics #27 (May 1939), also Batman's first appearance.

The Penguin runs a nightclub called Iceberg Lounge, which provides a cover for his criminal activities. Batman sometimes uses the nightclub as a source of criminal underworld information.

In the 12-part storyline "Hush", Edward Nygma (also known as the Riddler) is diagnosed with terminal cancer and hijacks one of Ra's al Ghul's Lazarus Pits to regain his health.

In the earliest Batman comics, Bruce Wayne dates the often-imperiled Julie Madison, an actress and socialite who eventually weds into European royalty, much in the manner of Grace Kelly. Julie first appeared in Detective Comics #31 (September 1939), only four issues after Batman's own debut.

Thomas Blake (a.k.a. Catman) turned to crime because he had grown bored with hunting and had squandered most of his fortune. He based his costume on Catwoman's disguise, and she was none too pleased about having her modus operandi copied.

Located on the outskirts of Gotham, Arkham Asylum is a psychiatric hospital where many of Batman's foes are sent for rehabilitation. Unfortunately, Arkham doesn't have a very good track record. Inmates escape on a regular basis, and those who are discharged often return to a life of crime.