The cover of the sequel features an illustration of the first book's signature orange-apple hybrid exploding, calling to mind Harold Edgerton's famous Apple with Bullet and the volcanic cover of L. Ron Hubbard's Dianetics. After reading the latest book, fans can look forward to a feature-length documentary directed by several filmmakers including Super Size Me's Morgan Spurlock and Alex Gibney, the Academy Award-winning director of Taxi to the Dark Side. The film, listed by IMDB as being in post-production, will either premiere at the Tribeca or Cannes film festivals in 2010.

There may also be a TV series in the works soon. "I met with approximately one and a half million network people and producers over the past five years, and for a variety of reasons we were never able to pull the trigger," Dubner said. "But we're psyched to give it a good try, and I think we have a good partner this time."

If you can't wait for the movie or the show, Dubner and Levitt speak regularly. The Walker Agency declined to say what the men charge as an honorarium, but BizBash, a publication that tracks the event industry, reported in 2006 that "Levitt can command as much as $40,000 for a speech." Dubner also declined to talk numbers, which is understandable. After reports in Fast Company, New York, and elsewhere about the eye-popping speaking fees paid to The New Yorker's Malcolm Gladwell, a journalist whose work is often compared to Dubner's and Levitt's, the author became the object of much derision from some quarters.

Speaking of derision, before SuperFreakonomics was even released it found itself under attack for its final chapter, which strayed somewhat from the usual (which is to say, unusual) areas of study by Levitt and Dubner, to take on global warming. The authors view climate change through a prism of what economists call "externality," what Dubner and Levitt describe as "what happens when someone takes an action but someone else, without agreeing, pays some or all of the costs of the action."

Without denying that the earth's climate has changed, they attempt to cool (so to speak) some of the hysteria surrounding global warming, in part by visiting with scientists at Intellectual Ventures, a company owned by former Microsoft CTO and all-around big brain Nathan Myhrvold, who tells them, "Most of the warming seen over the past few decades...might actually be due to good environmental stewardship!" (Italics are theirs.) Other IV scientists tell them things that might make Al Gore gasp: That rising sea levels "aren't being driven primarily by glaciers melting" and that projections of whole cities and countries subsumed by rising seas (as seen in An Inconvenient Truth) may be exaggerated.

"I really liked the idea of writing about the notion...of global warming as a product of negative externalities," Dubner told Portfolio.com before the book came out. "That's the way an economist would frame it."

Some environmentalists—and at least one economist, Nobel Prize winner, and Times columnist Paul Krugman—wished they hadn't framed it at all.

The Union of Concerned Scientists denounced their work, saying "The authors appear to have taken a purposefully contrarian position on climate-change science and economics. While such a position may help draw attention to their book, their reliance on faulty arguments and distorted statistics does a disservice to their readers." Environmental sites like Climate Progress, (a part of the Center for American Progress), Treehugger.com (owned by Discovery), and RealClimate.org (owned by the Guardian) also took shots at their methods and interpretations in the days before SuperFreakonomics hit stores.

Outside of the science and environmental community—and from within the walls of the very institution that brought Dubner and Levitt together—Krugman has used his Times blog, The Conscience of a Liberal, to criticize them in multiple posts. The Nobel Prize winner writes that Dubner and Levitt's reading of economist Martin Weitzman's 2008 paper "On Modeling and Interpreting the Economics of Climate Change" may be flawed.

"I read Weitzman’s paper," Krugman blogs, "and have corresponded with him on the subject—and it’s making exactly the opposite of the point they’re implying it makes. Weitzman’s argument is that uncertainty about the extent of global warming makes the case for drastic action stronger, not weaker." (Krugman is the critic quoted above saying Dubner and Levitt have gone "way over the line" and were trying to "shock the bourgeoisie.")

Dubner is not backing down. In a long post on his and Levitt's Times-hosted blog headlined Global Warming in SuperFreakonomics: The Anatomy of a Smear, he takes on his critics directly and writes, "Levitt and I…look forward to debating the content of the chapter itself, the actual ideas and conclusions.

"Will a lot of people argue with them? Absolutely."

Will a lot of people buy the book to see just what the controversy is about? Absolutely. In his and Levitt's stepping into this controversy here, one is reminded of something Dubner wrote about his partner six years ago when their relationship was still that of journalist and subject. There were no blockbuster bestsellers, no foreign translations, no movie and TV deals, and no speaker's fees back when Dubner wrote of Levitt: "There is nothing in his appearance or manner, in other words, that suggests a flamethrower. He will tell you that all he does is sit at his desk, day and night, wrestling with some strange mountain of data. He may be an accidental provocateur, but he is a provocateur nonetheless."

This time the provocation may not be so accidental. But now, instead of coming from an academic largely unknown to the outside world or from a sleeper pop-economics book no one expected to cross over, the provocations are coming from the stewards of an established, lucrative brand, the virtual co-chairs of Freakonomics, Inc. With their global-warming chapter, Dubner and Levitt may risk alienating some readers and—worse yet—opening up their methods to critics who aim to discredit them.

In the coming weeks, as their new book inevitably climbs the bestsellers lists—and as the movie based on their work comes to theaters—their critics will probably only get louder and more vehement.

Things may get a little freakier for Dubner and Levitt. Superfreaky, you might even say.