Few historians can hope to match the tremendous success of the history-trained fiction writer Caleb Carr, whose book, The Alienist (1994) was a chilling look at the world of late 19th-century America through the eyes of a detective and practitioner of early criminal forensics. Carr made the New York Times list and attained a reputation for engrossing (if rather lengthy) novels. Michael Shaara’s equally impressive Killer Angels (1974) has become a classroom staple for Civil War courses and was the basis for Ronald Maxwell’s movie, Gettysburg. More recently, Newt Gingrich and Montreat History Professor Bill Forstchen’s trilogy of Civil War books, Gettysburg (2003), Grant Comes East ( 2005), and Never Call Retreat (2005) continued the Killer Angels tradition, then one-upped Shaara, by offering a counterfactual evolution of the Civil War.

What makes a historian become a novelist? Having just released my first novel—September Day, a thriller about 9/11 featuring, predictably, a college professor as one of the heroes—I can offer some thoughts. First, one of the knocks on anyone writing history of any recent or current events has been that “not enough time has passed” or that “the evidence is not all available.” True enough. But is sufficient evidence available to tell a believable story that is true as far as one knows it? Yes. Novels can offer scholar a way out of that box—a means to explore what he or she thinks is true, even if every last piece of evidence is not at hand.

Second, a novel provides a path to reach people who, for whatever reason, hate footnotes. The very presence of the apparatus of “scholarship” intimidates some, but I suspect more often than not it just irritates others, who a) don’t plan to look at sources in the first place, and b) who trust a professional enough to think that the writer wouldn’t deliberately lie.

Third, and probably most relevant, fiction writing allows historians to deal with human motivations on a level that can never be fully satisfying in the non-fiction realm. Sgt. Buster Kilrain’s discussion of slavery with Col. Joshua Chamberlain in Killer Angels permitted Shaara to pour into Kilrain’s character a variety of views held by Union soldiers as to why they were fighting. Yet the fact that many characters are fictional often belies the depth of real historical research behind the actual figures, such as Union Railroad genius Henry Haupt, in the Gingrich/Forstchen trilogy. Suffice it to say, there is not a non-fiction work around that can capture the importance of railroads and the quartermaster corps as well as Grant Comes East.

Fiction writing also allows us to explore the likely attitudes and motivations—from extensive existing evidence—of people we can no longer interview, such as I do in September Day with Mohammad Atta or the passengers of Flight 93. Admittedly, this can give rise to myth—the notion that Davy Crockett “went down swinging Ol’ Betsy on a wall at the Alamo,” when more recent research suggests he may have been killed early or, on the other hand, taken prisoner to be executed later; or the famed Custer’s Last Stand, when archaeologist Richard Fox has revised the Battle of the Little Big Horn based on the most reliable evidence of all, forensic evidence from the battlefield. On the other hand, I suspect that many novelists, despite the disclaimer at the front of each book, rely heavily (as I did) on real people to provide virtually every detail of their characters. (Who is whom in September Day, I won’t say.) More than a little fact is critical in any persuasive novel: I included real conversations from the Twin Towers and from Flight 93, as well as President Bush’s National Cathedral address. The test, I guess, is whether or not most readers say, “Yeah, that could happen.” In Gettysburg, Gingrich and Forstchen were so convincing that I (having not read a hype or review, hence not knowing that the book was a “counter-history”) was 100 pages into the book before I first said, “Waitamimmit! Longstreet didn’t do that!” (One editor, in rejecting the manuscript of Gettysburg, was actually so dense as to think the authors got it wrong. “Don’t they know who won?” he wrote.) In the end, historical fiction is far less about having history turn out how we want it to than in explaining in a more satisfactory manner why it turned out the way it did. Oh, and perhaps most important of all, writing historical fiction is fun.