In 2010, John D'Agata's book "About a Mountain" was released, billed as the story of plans to locate a nuclear waste storage facility near Las Vegas, at Yucca Mountain. The book received acclaim for its weaving of seemingly unrelated stories -- the suicide of a teenager who jumped from the top of the Stratosphere hotel, the lifespan of language, helping his mother move -- and of the connections that pulled these stories together. Some time after publication, it came to light that D'Agata had "massaged" some of the facts, making minor changes in details to make the overarching story flow better. He didn't deny it; in fact, it was never something he was trying to conceal, but part of his approach to pushing the limits of essayistic writing.

Before it became a book, it was intended to be an essay for a national magazine that rejected it on the basis of factual inaccuracies. Another magazine took it on, and gave it to a fact-checker named Jim Fingal to examine. Knowing that D'Agata's interpretations of facts had torpedoed the essay earlier, Fingal set out to be as thorough as possible. He discovered early on that inaccurate facts were far outnumbering accurate ones. When he brought this to the attention of the editor, the editor put Fingal directly in touch with D'Agata to streamline the process of verifying the accuracies and inaccuracies.

Which brings us to "The Lifespan of a Fact," a reproduction of the essay, alongside the correspondence between these two men. Early on, Fingal feels obligated to ask D'Agata if he's concerned about his credibility with the reader, given that the accumulation of these "massaged" facts could well undermine the veracity of the work as a whole. D'Agata makes it clear that not only is he not concerned, he's annoyed at what he sees as Fingal's inability to see past a black-and-white, true-or-false interpretation of every word in the essay.

What follows is an enthralling back-and-forth conversation over several months in which these two men dove deep into what it means to be a writer, what it means to call something "nonfiction" and where the lines are between creativity and honesty. Questions about what's more important -- having a source that confirms a claim (but is probably inaccurate) or changing the claim so that it's genuinely accurate? -- lead to anger and frustration, as the fact-checking becomes a matter of "moral responsibility" in writing. Given that we live in a climate of spin, where everything is up for debate depending on how it is presented, this book provides essential and exciting reading for anyone interested in how we define "the truth."

Matthew Tiffany is a writer and psychotherapist. He blogs at