THE LAST TRAIN TO ZONA VERDE. By Paul Theroux. Houghton Mifflin Harcourt. 353 pages. $27. Ebook $27.

Maybe the most astonishing thing about Paul Theroux’s travel writing is that a lot of people don’t like it. He’s considered the grumpy old man in the field, continually railing on about this or that disruption of authentic culture by modern incursions instead of tour-guiding hungry escapists to the wonders of Bora Bora.

This is his genius. Theroux is a real-world traveler: He drops you smack into the dirt and desires of a land and its people.

In “The Last Train to Zona Verde,” the chapter called “Three Pieces of Chicken” is one of the finest bits of travel gristle you can chew. Stranded in the Angolan bush when the folk taxi he’s riding in breaks down, he writes:

“We drank beer, we muttered, we listened, and then it occurred to me that if I didn’t claim a place in the car I would have nowhere to sleep. While they were talking, I went back to the Land Cruiser. I cranked the seat into reclining position, covered myself with my jacket, and to the drumming in the distance and the muttering of boys sitting on the steps of the shed, I subsided into sleep. From time to time I awoke, and I was surprised by the gusto of the drumming, but in the darkest hours of morning, it ceased. ... In daylight the place was ugly, more littered and beat up than it had seemed the day before.”

The chapter revolves around a bucket holding three blackened limbs of skinny chicken, covered with black flies, offered for sale. He turns them down at first, but then buys them one by one because there’s nothing else to eat.

“The Last Train to Zona Verde” might well not be the last go-round from the prolific Theroux. It is, after all, his 46th book of travel, fiction or criticism. He took off on the trip to Southwest Africa after finishing a novel. But it has the feel of his coda. The septuagenarian started his travel life as a Peace Corps volunteer in Malawi in the 1960s and has returned repeatedly to trek and write about a continent he unabashedly loves.

This time, though, he’s brooding about his age and mortality in the early chapters, then in the closing chapter, “What Am I Doing Here,” he is coming to terms with his disillusion about what’s become of West Africa:

“Of course, I could put my head down and travel farther, but I knew what I would find: decaying cities, hungry crowds, predatory youths and people abandoned by their governments, people who saw every foreigner as someone they could hit up for money.”

Theroux takes you on a rocky safari across infringed wilds, disenfranchised poverty and coven luxury. He introduces you to a boil of angry indigenous peoples and unsettled migrants you won’t meet on an itinerary tour.

This trek opens with him on a spear hunt in Namibia, stepping over termite hills with bush people, one of the world’s oldest cultures, “pouch-breasted women laughing among themselves, an infant with a head like a fuzzy fruit bobbing in one woman’s sling, men in leather clouts clutching spears and bows.”

Go on, turn the first few pages. Then I dare you to put it down.

Reviewer Bo Petersen is an environmental reporter for The Post and Courier.