Wizard’s website covers the story, but here’s the highlights:

• The Joker was created by Batman artist and political cartoonist Jerry Robinson
• Robinson launched a media campaign to free the imprisoned Uruguayan political cartoonist Francisco Laurenzo Pons
• Organized a major syndicate for editorial artists to control their own work
• Helped Jerry Siegel and Joe Shuster get a much needed financial settlement and their byline restored on their famous creation Superman