A new book, due out in April, will shed some light on the story of the Superman radio shows that took on the KKK back in 1946—and hopefully straighten out the record once and for all. Several versions of this story have made the rounds over the years, and the basic facts are not in dispute: In 1946, the Adventures in Superman radio show ran a 16-episode arc titled "Clan of the Fiery Cross," in which Superman took on an organization that had many similarities to the Ku Klux Klan. (You can listen to it here.)
Much of the background material from the shows came from journalist Stetson Kennedy, who infiltrated the Klan and then wrote about it. Kennedy claimed the Superman shows included real Klan code words, causing great frustration to the real Klan leaders, who had to change them after every episode. (Our sister site, Comics Should Be Good, discussed the story as part of their Comic Book Urban Legends series.)
Author Rick Bowers researched the matter at length for his new children's book, Superman Versus the Ku Klux Klan, and concluded that, although it makes for a great story, it just ain't so. As he said to J.L. Bell, in an interview at the Horn Book site,
The reality is that “Clan of the Fiery Cross” — while dramatic and to a degree realistic—did not contain actual code words and did not force the Klan to scurry about changing their code words. Nevertheless, it is important to acknowledge the Superman producers for creating such a powerful program and to give a nod to the anti-Klan efforts of Stetson Kennedy — even if he was prone to exaggeration and tended to grab credit.
The code-words story was included in the first edition of Freakonomics, but the authors amended the story in later editions. Bowers said he began working on his book after that, and the public debate led him to research the matter carefully. The truth, as is usually the case, is more prosaic than fiction—but still pretty good!