Richard Flanagan has an important story he wants to tell, with a universal theme about the human heart underlying it. A Tasmanian writer, Flanagan has shown in his previous work that he is vividly haunted by his island’s violent history. This time around, in Wanting, he turns (or perhaps tosses — he gives the impression of having a nightmare) to the horrible story of the near-extermination, much of it deliberate, of Tasmania’s aboriginal population at the hands of its white settlers. A good deal of his material and all of his personages are factual; Flanagan has gathered a sheaf of history’s pages from what would appear at first to be unrelated sources and then gone to work like a magician with a newspaper, cutting away the majority before unfolding a paper chain of associated figures.

The first person in the chain is Mathinna, a Tasmanian girl born in a squalid resettlement camp in 1835, when her people were already mostly dead, and the rest dying. Mathinna has been noticed, just barely, by history because she spent two years of her childhood at Government House in the Tasmanian capital of Hobart, where the governer and his wife, Sir John and Lady Jane Franklin, taught her alongside Sir John’s daughter, Eleanor. She was evidently a lively and attractive child (a portrait survives of her, looking bright-eyed in a red dress), but the Franklins did not adopt her, and when they left the island, she was sent to an orphanage, and later back to the resettlement camp; very little is known of the rest of her life, except that it was short and probably sad.

Sir John Franklin is the second person in the chain — and yes, this is the John Franklin of the Franklin Expedition, which sailed off to discover the Northwest Passage and instead fell off the edge of the world, thus becoming its own fabled quest object, as the presumptively widowed Lady Jane organized a number of highly publicized expeditions to go in search of her husband.

Lady Jane leads us to Charles Dickens, because nine years after Sir John disappeared in a glare of white, another explorer found evidence, bolstered by Inuit testimony, suggesting that Franklin and his men had perished from cold and hunger, and that some of the men had resorted to cannibalism. Lady Jane, outraged at this slur on English fortitude and good sportsmanship, enlisted Dickens to write a rebuttal, which he did, in his magazine Household Words. Dickens’s argument — that savages give in to unrestrained desire, whereas what makes a man civilized is his ability to withstand temptation — is so impassioned, it suggests some inner turmoil. Dickens then had his friend Wilkie Collins write a play about northern exploration called The Frozen Deep, which sublimates the theme of cannibalism into sexual possessiveness. In Collins’s play, Richard Wardour hungrily loves a woman who in turn loves a different man, and Wardour ultimately sacrifices himself so that the woman and his rival may live happily ever after. Dickens himself played the part of Wardour onstage — and proved to be a sensation, as he seemed to live the role more than act it. During the production he met the next person in the chain, the 17-year-old actress Ellen Ternan. Nine months later, the 45-year-old Dickens left his wife and embarked on a secret liaison with Ternan that lasted until his death.

This is wonderfully workable material, which Flanagan has grouped into alternating chapters, first telling Mathinna’s story, then jumping ahead a few years to tell Dickens’s, then back again. It’s easy to see why Flanagan was attracted to the idea of placing these linked lives in close proximity so that, like wine glasses in a glass harmonica, they would set each other vibrating on sympathetic frequencies. He says as much in his Author’s Note: “The stories of Mathinna and Dickens, with their odd but undeniable connection, suggested to me a meditation on desire — the cost of its denial, the centrality and force of its power in human affairs.”

But perhaps exactly there — with that terse formulation describing his intentions — is to be located the source of the limitations of this novel. In other words, it seems that Flanagan knew from the beginning what kind of novel he wanted to write, what points he wanted to make, and then proceeded with energy and enthusiasm to make them. This is a wise procedure for writing a historical essay, or perhaps a “meditation,” but less so for a novel, which, even if not fully a “baggy monster,” in Henry James’s phrase, should have at least something monstrous about it, by which I mean something puzzling, elusive, irreducible to one of those theme papers your high school English teacher was always fatuously demanding that you write. I couldn’t locate a moment in this book where I sensed that Flanagan was surprised at where the book was taking him; thus none of its developments surprised me.

The prose seems overdetermined from the beginning, when the reader turns from the title page to the two epigraphs, one from Dostoevsky and one from Ecclesiastes, both of which characterize and use the word “wanting.” It continues in that vein, hammering out the theme of desire vs. discipline, savagery vs. putative civilization: “After all, wasn’t that control precisely what marked the English out as different from savages?” “he mark of wisdom and civilization was the capacity to conquer desire, to deny it and crush it.” “You see, Wilkie, that is Franklin’s experience and his lesson. We all have appetites and desires. But only the savage agrees to sate them.” “A savage, my dear Wilkie, be he Esquimau or an Otaheitian, is someone who succumbs to his passions.” “No moment was to be wasted, and all reckless passions were to be subjugated to the discipline of industry.” “The distance between savagery and civilisation is measured by our control of our basest instincts.” And so on, and on — all the way to the last word of the last Dickens chapter: “And he, a man who had spent a life believing that giving in to desire was the mark of a savage, realized he could no longer deny wanting.”

There’s also too much about white vs. black, about frozen seas and frozen hearts, for the good of the novel. One particularly awkward patch stems from Flanagan’s overt linking of the cannibalism theme to Dickens’s memories of his early love for, and rejection by, Maria Beadnell. “Maria Beadnell and her vile family had treated him as little better than a corpse to play with, to feast upon for their own amusement.” As if that were not already too much, here’s this, four pages later: “Had he not yearned to bite into Maria Beadnell’s thighs as keenly as the Esquimaux had wanted to feast on old Sir John’s gentlemanly drumsticks?” (That’s got my vote for the worst sentence of 2009.)

These faults of emphasis are on the level of language; there are others on the level of plot. Whenever a novelist tells a story based on historical fact, there’s a temptation either to fill in a lacuna in the record with an invented incident that metaphorically nails down a point the writer worries would otherwise remain nebulous, or even to change something in the record to accomplish the same end. Flanagan does both. For example, history tells us nothing about Sir John Franklin’s attitude or behavior toward Mathinna. But the larger story here is the perfectly true, and terribly painful, story of the violation of the aboriginal Tasmanians’ bodies and culture at the hands of whites. Therefore, in this novel, Sir John Franklin rapes Mathinna.

As for changing facts — when Dickens acted the part of Richard Wardour in The Frozen Deep, he did not play opposite Ellen Ternan (who had a minor role in the play), but her sister Maria. In a scene that reads far too much like the mechanical maneuverings of romance fiction (besides being overly reminiscent of the movie Shakespeare in Love), Flanagan has Maria fall ill on the night of the final performance, so that Dickens can play opposite Ellen, both of them in roles freighted with a heavy symbolic relevance to the romantic drama developing in their private lives.

This is not to say that a writer should never do such things; but it’s a dangerous temptation, because it’s easy, and the usual result is to overdo it. In Flanagan’s case, the more he ties together his wine glasses, the less they resonate. Or to ring a final change on his own metaphor, his passion for making his staged meanings obvious to the back row has overwhelmed the discipline of his craft.