Christopher de Bellaigue’s new book begins with the story of a journalistic blunder, the author’s own. In 2001 Mr. de Bellaigue wrote a long essay for The New York Review of Books about Turkey’s tangled history. It was a topic he thought he knew something about. At the time he was living in Istanbul and working as a foreign correspondent for The Economist. His essay had barely arrived on newsstands, though, before complaints began to pour in. It turns out that Mr. de Bellaigue, while describing the age-old ethnic conflict between Turks and Armenians, declared that “some half a million” Armenians “died during the deportations and massacres of 1915.” Unknowingly, he had stumbled into bitterly contested territory. James Russell, a professor of Armenian studies at Harvard, was among those who wrote to rebuke him. Three times that many Armenians “were murdered,” Mr. Russell replied, “in a premeditated genocide.” Mr. Russell’s letter to The New York Review of Books continued: “If a reviewer wrote that only a third of the actual number of Jewish victims of the Holocaust had died, or that their deaths came about because they had rioted, or elected to make war against the German government, would you print it?” Mr. de Bellaigue was appalled at the tone of Mr. Russell’s letter, he writes, and at the possibility that he had made serious mistakes. He was shattered when Robert Silvers, the venerable editor of The New York Review of Books, scolded him over the telephone for appearing to be an apologist for the Turks. Chastened, Mr. de Bellaigue — a talented British journalist and the author of “In the Rose Garden of the Martyrs: A Memoir of Iran” (2005) — set out to discover the truth about what happened nearly a century ago between the Turks and the Armenians. The result of that quest is “Rebel Land: Unraveling the Riddle of History in a Turkish Town,” a deeply unconventional book that is as much memoir as proper history. It’s a murky and uneven book, too, one that Mr. de Bellaigue’s twitchy intellect and acid prose can’t quite rescue. Mr. de Bellaigue lets us know early on that “Rebel Land” is not going to be, at bottom, a research project. “I would not pore over books in libraries and faculties,” he declares, nor will he “solicit help from the Kurdish and Armenian lobbies.” He decides to “go to the back of the vessel and mix it in steerage with the forgotten peoples. From them I would get the story, gritty and unfiltered, of their loves, their losses and their sins.” What this jaunty bit of cultural condescension (mix it in steerage?) means in practice is that Mr. de Bellaigue begins to spend a lot of time in a small town in southeastern Turkey named Varto, in a district (also named Varto) that was caught up in the turmoil of 1915. Thousands of Armenians once lived there, and the ruins of their churches linger still. This place is a far cry from the cosmopolitan Turkey that Mr. de Bellaigue knew and loved in Istanbul. Speaking of that urban Turkey, the one that mostly prefers to deny its complicated past, he writes, “I would now go behind its back and betray it.” So Mr. de Bellaigue goes to Varto and begins to poke around. Because he is a keen observer and a natural satirist — I would like to read a novel by him — the parts of “Rebel Land” that are akin to travel writing are shrewd. He is good on people, observing one man’s “flowery nose” and “grenadine complexion,” another’s “white parabola” of a mustache, yet another’s “precarious nail-bitten superiority.” Mr. de Bellaigue is a mordant sensualist, noting how a river flows into “curvaceous oxbows” and how boots “sucked and popped” through mud. He is particularly attentive to his meals, enjoying “mezes of superlative quality,” “a delicious apricot cake” and noting how one local man enjoys deep-fried local trout with rocket and radishes. He describes Varto itself as “this curious place with a name like a cleaning detergent.” There is Kafkaesque humor, too, in the way the local authorities trail him, and in the way he tries (and usually fails) to get the locals to trust and to talk to him. Mr. de Bellaigue’s peppery asides rub up awkwardly, however, against the main story he is trying to tell in “Rebel Land,” one that doesn’t lend itself to pithy aperçus. The arc of his narrative becomes lost amid the place names and rumors and dimly remembered family stories. He complains that he “might be told three or four versions” of every event, and the reader begins to feel his pain. This is a book that has a two-page dramatis personae at the front, of the kind that makes your heart sink. Mr. de Bellaigue does not do enough to separate all these living and historical people, to make them distinctive, and they become a jumble on the page. As his book progresses, Mr. de Bellaigue begins to limit his focus to the crucial questions, notably this one: what happened to the Armenians of Varto? His book becomes a kind of intellectual, emotional and forensic detective story. He delivers, piece by piece, a summary of the Armenians’ case against the Turks and he blasts the Turkish historians who, he feels, have whitewashed a portion of their country’s history. Ultimately, he writes, “the big historical question is not whether very large numbers of Anatolian Armenians met with a violent end in the spring and summer of 1915, but whether or not the killings took place by fiat.” In other words, was it genocide or merely the actions of a few bad men? Mr. de Bellaigue worries that “a genocide fixation” has blinded both sides to all shades of gray. “What is needed is a vaguer designation for the events of 1915, avoiding the G-word but clearly connoting criminal acts of slaughter, to which reasonable scholars can subscribe and which a child might be taught,” he suggests. “By raising knowledge about this great wrong, a way might be opened to a cultural and historical meeting between today’s Turks, Kurds and Armenians, for they were not alive in 1915, and need not live in its shadow.” The gimlet-eyed and sensible Mr. de Bellaigue proposes all this, and then immediately realizes his cosmic folly. “But no; this is the prattle of a naïf,” he writes, “laughable, unemployable.”