The writing career of Paul Theroux—twenty-some novels, countless short stories, and many books of travel—now spans four decades and shows no signs of slowing down. Theroux’s travel books, beginning with the highly successful Great Railway Bazaar (1975) and featuring most recently a return trip (Ghost Train to the Eastern Star, 2008), add up to a distinctive achievement in that genre. By contrast his novels seem to have been overshadowed, not taken with full seriousness. Early on, in one seven-year stretch, he produced such rereadable ones as The Black House, Picture Palace, and The Family Arsenal, peaking with The Mosquito Coast, his best-selling (though not his best) novel. Since then he has written novels that perhaps have not always inspired readers to keep up: a weird venture into sci-fi (O-Zone); a scarifying look at a sexual misfit/killer (Chicago Loop); and two longish episodic “personal” ventures, My Other Life and My Secret History, which for all their lively parts didn’t quite come off. Increasingly the novels have been set in non-Anglo-American habitats: Hawaii (Hotel Honolulu); Hong Kong (Kowloon Tong); Ecuador (Blinding Light); India (The Elephanta Suite, The Dead Hand), and now Africa. The Lower River is both a revisiting and probably a farewell to that continent, specifically to Malawi, where two of his earliest novels were set; it is also one of Theroux’s darker explorations of a world as “other.”

Ellis Hock, age sixty-two, is a retired store owner in Medford, Massachusetts (Theroux’s boyhood town). At loose ends following the demise of his marriage, he decides to revisit the one place where he was really happy—Malawi, where, four decades back, he (like Theroux) worked as a Peace Corps teacher. Hock remembers those years as a time when he felt “absolutely disconnected from home” and proud in his efforts to build a school in Malabo, located on the remote Lower River. Hock returns to Malawi, where he is taken under the solicitous-sinister wing of Manayenga, a grandson of someone he knew back then. Under Manayenga’s guidance, Hock “submitted to the gravitational pull of the Lower River,” and soon realizes just how isolated he is—“as though he were not just on a faraway moon but trapped on its dark side, in an underworld.” With no electricity Hock experiences “early nights and twelve hours of equatorial darkness, no computer access, no internet, no fax machine. He had asked to be disconnected.... Now, he was buried in utter silence.”

His companions consist solely of a devoted young woman, Zizi, granddaughter of a woman with whom Hock fell in love long ago, and a deranged dwarf, Snowdon, whose only word is “Fe-dee-dom” (freedom). His nonhuman companions are a collection of snakes (an old hobby of his) that he keeps in a sack along with his dwindling supply of cash, which Manayenga draws on liberally. Hock develops malaria and while ill misses a visit from a food-supply agency, Manayenga having neglected to inform the visitor of a sick white man on the premises. (This event reminds us of Evelyn Waugh’s A Handful of Dust, where the captive Tony Last, who must read and reread Dickens to his “keeper” Mr. Todd, is drugged by Todd and misses possible rescue by a visitor.) When Hock talks about going home to Medford, Manayenga reproaches him: “This is your home, father.” Realizing that he is the victim of a shakedown, Hock makes several unsuccessful attempts to escape; gradually he becomes a physical ruin, “trapped in a rotting province that he had once known as promising.”

This, then, is a novel in which things go from bad to worse, to even worse than that, and finally to an alleviation at the book’s end (I won’t reveal it) that is not quite to be believed. Throughout, the writing is strong and assured, especially when describing the stricken African landscape to which Hock has returned. But what is Theroux up to in charting so ruthlessly Hock’s degradation and disintegration? Is it a cautionary tale? A novel of pure adventure? The novelist Norman Rush addressed this problem in the New York Review of Books (June 7), asserting that The Lower River should be set off from the main body of both Theroux’s fiction and travel writing. Rush describes the unmistakably personal voice Theroux has created in his work—that of a “smart, irreverent, wry, democratic, honest, undeluded, intimate American,” but finds no such voice or character in The Lower River. It is instead a notably successful example of “straight horror/fantasy genre writing,” one that provides “frightening fun” for the reader. Yet this explanation of the novel doesn’t address how and why a veteran writer now entering his seventies should choose to limit and simplify his powers as a novelist in this way. To suggest a possible answer, a brief look back at Theroux’s earlier fiction is in order.

If novelists are expected to “develop” over a career (but remember Oscar Wilde: “Only mediocrities develop”), Theroux to my judgment has failed to do so: the four early novels mentioned above can’t be seen as moving on to better, deeper achievements. Perhaps I overrate these books because of the pleasures and excitements of reading Theroux for the first time; yet reread now they hold up very well indeed. The Family Arsenal is a gripping tale about some 1960s London revolutionaries, told in a manner indebted to Henry James, Joseph Conrad, and Graham Greene; London streets and pubs are evoked in a way Theroux would seldom choose to do later. Picture Palace, a first-person tale about a female photographer and her history, is attractive and still surprising for the sharp, idiomatic originality of its wise-girl observations. Theroux also has an uncanny ability to render a sentence as it actually sounds when issued from the voice of an imperfect speaker; thus “I got something doing on Saturday,” spoken by a character in The Mosquito Coast named Tiny Polski, comes out as “sumthun doo-un on Saddy.”

In his review Norman Rush speaks of the The Lower River, with its notable lack of such high jinks, as if the novel were sui generis, an oddity in the Theroux fictional canon. But looking back at some of his recent efforts, one is hard pressed to find much of the comic in their relentless pursuit of one or another misguided “hero.” Blinding Light, the novellas that constitute The Elephanta Suite, and A Dead Hand, the novel immediately preceding the new one, are pretty bare of the old Therouvian jeux d’esprit, except for two scenes that remind us of Theroux as trickster: the party in Blinding Light at which Bill Clinton shows up, and the “interview” in A Dead Hand between the narrator and “Paul Theroux”—both of which feel like specialty acts, though very lively ones. When Rush states that there is “no way to derive a sensible maxim” from The Lower River, he is right, but wrong to define this quality as pertaining merely to the new novel.

Interviewed recently on PBS, Theroux was asked how he wanted a reader to behave in relation to his novel. He replied that first and foremost he hoped readers would be drawn in enough to be caught up in the action of the book as it unfolds. Only later would it be time to speculate about larger matters. At the very end of Picture Palace, when photographer Maud Coffin Pratt is celebrated at a party, she feels wholly detached from the proceedings and thinks,

I had made a virtue of being anonymous. I had abided by it and why not?... It was too late to reveal myself, for there was a point in obscurity beyond which exposure meant only the severest humiliation. It was better to continue anonymously and finally vanish into silence.

It may seem paradoxical, or just plain perverse, to associate Theroux the novelist, who has made more than one personal appearance in his books, with anonymity. But looking back over the disparate character of books so various and, often, sensationally engaging, one is baffled in the search for some unmistakable presence behind or within them. This distinguishes Theroux from honored predecessors like Conrad and Graham Greene, and also from near contemporaries like John Updike and Philip Roth. In the end, instead of trying to locate the character or the “center” of this undeniably productive man of letters, it may be enough simply to reread his novels and be drawn into them all over again.