For half a century, the novelist and travel writer Paul Theroux has been traversing continents—often crammed into an overcrowded bus or wedged into a packed train car. His international wanderings began as a Peace Corps volunteer in Malawi in 1963, and in 1975 he published his first travel book.

The Great Railway Bazaar, which took him from Europe across Asia and back by rail, is regarded by multiple generations of backpackers as a classic of the form. Now 72, Theroux splits his time between Hawaii and Cape Cod. This month he publishes his 15th travel book, The Last Train to Zona Verde, in which he sets off from Cape Town and journeys up through Namibia and Angola before cutting his trip short.

Theroux recently spoke with National Geographic adventure editor Peter Gwin about why this was his last ambitious overland trip in Africa, where he's looking to go next, and how he sees echoes of 1980s London in the recent bombings in his native Boston.

Not to jump too far ahead, but your book ends with you abandoning your journey up the western side of the African continent. I was left wondering if you, a longtime Africa observer, have given up on the continent?

No, I've given up on thinking I could travel overland for long distances in Africa. After Angola, I realized that it would be impossible for me to go further. I previously took a trip from Cairo to Cape Town, which I wrote about in Dark Star Safari. It was a long difficult trip, so I thought I would resume it in Cape Town. I had hoped to go up to Nigeria and Mali and maybe end in Timbuktu, but I realized that I couldn't do that.

The idea of traveling in Africa for me is based on going by road or train or bus or whatever and crossing borders. You can't travel easily or at all through some countries. The Congo is impossible, and traveling from capital to capital is no fun. You don't learn anything. So I haven't given up on Africa, but I've given up on the idea that I would take a long interesting trip. I don't feel I'm too old for it, but the idea of a nine-hour bus ride from one horrible city to another is out of the question.

In your last chapter you talk about how there are too many people in Africa, the cities are in disarray, that it's a dysfunctional landscape. Some of this I sensed was the weariness of a traveler at the end of one of these long trips.

Africa is really a place for the wealthy traveler. It's got some nice hotels, but they're very expensive hotels. It doesn't really cater to the backpacker or to the overland traveler. Really it's two places: It's the place for wealthy people to go on safaris and then it's for aid workers or volunteers, people teaching in a school, where you stay in a village or a town, and you get on with your job.

If Africa is ruled out for you, where do you still see an opportunity for the kind of traveling that you want to do?

Most places. China is open, though I'm not particularly interested in going back to China again. I visited in the 1980s and wrote Riding the Iron Rooster. Russia is a place you could take a long trip. South America is another; so is India. So that kind of travel is still possible in most places.

The place that interests me most, actually, is the United States. I've realized that I haven't traveled much in the States. There's a lot to see. In two days of travel you could get from Washington to New Orleans and get through a really interesting part of the States through the South.

We live in a country where an area that is—I don't know if dysfunctional is the word for it, but certainly undeveloped or underdeveloped, where there is a high infant mortality rate, AIDS is a problem, drugs are a problem, substandard hospitals, substandard schools. But we have great roads, great roads. So you can go anywhere in the States. I mean you can get to the furthest limit down a great road. What you'll find there: people living in shacks or old rotten trailers or towns that have lost all their industry. But that to me is worth doing, and it's what's taken my interest at the moment.

Some observers have debated whether Western-style democracy will work in Africa, especially given that its borders were largely drawn by colonizers. Is that something you've thought about during your extensive travels in Africa?

I think about it a lot. I do think that the system in place ought to produce a reasonable person to govern, or it should produce reasonable people. It hasn't. It's produced a lot of tyrants. It's produced a lot of people who won't let go of power.

The president of Angola, dos Santos, has been there for more than 30 years. In Malawi Banda was there for nearly 30 years. It goes on. The guy in Burkina Faso, Compaoré, has been there for almost 30 years. In Zimbabwe, Mugabe's been there since 1980. So yes, you wonder if democracy is the right system. I think it's the right system, but people won't let go of power.

There has been a sea change in world politics and technology since you wrote The Great Railway Bazaar. How has any or all of that changed your approach to traveling over the years?

When I left to do The Great Railway Bazaar, I just had money on me. I had traveler's checks. I didn't have a credit card. Can you imagine traveling for four and half months with no credit card? Seems impossible. I didn't have a phone. I only made two phone calls in four and half months. So I sent letters home. I got mail at various places. The change in travel since I took that trip in 1973—40 years ago—has been astonishing. Now you can stay in touch, and you can carry credit cards and not worry about carrying large sums of money. My family knows where I am. When I took the Great Railway Bazaar trip, my family didn't know where I was. My letters arrived weeks after I left the place. I would write a letter saying I'm in Istanbul on my way to Tehran or I'm in Afghanistan on my way to Pakistan, and by the time my wife got the letter I would be way beyond Pakistan.

But isn't there something freeing about that sort of travel? Being completely disconnected in such a way that you're forced to focus your attention on the place you are in at the moment?

I agree that it's very liberating to just disappear, very liberating. The different part is carrying money, and I suppose making onward plans. Though there's something liberating about not making plans if you've got plenty of time at your disposal. Yeah, I miss that. I really do miss that. I'm not a big fan of carrying a phone or even of being in touch for that matter. But it's safer with those things, so there is a trade-off. You can still disappear but you have to be very deliberate about it.

At the end of Last Train to Zona Verde, you quote Albert Camus's exhortation: "Write the story of a contemporary cured of his heartbreaks solely by long contemplation of a landscape." Is that your view of the primal underpinnings of travel, the need to disconnect from your daily life to contemplate a different landscape?

Yes, I think so. The two impulses in travel are to get away from home and the other is to pursue something—a landscape, people, an exotic place. Certainly finding a place that you like or discovering something unusual is a very sustaining thing in travel. In this book there was a place in Angola where I got stuck, and I discovered something happening there. It's in a chapter called "Three Pieces of Chicken." There was a sort of nobility ceremony, called efendula. I thought, this is interesting. I'm learning something. This is a good reason to be here.

How has your approach to writing changed over the course of your travel books?

I do it exactly the same way. I had to discover how to write a travel book when I wrote The Great Railway Bazaar. I had lived in a lot of different places—Africa, Southeast Asia, Britain—but I had never regarded myself as a travel writer. I had written fiction with backgrounds based in the places I had been. I had to work out what to make notes about. I had always kept a sort of diary or a journal, but not in the extensive way that I eventually did. So on my first travel experience, setting off on this journey in 1973, I had a notebook, and I wrote everything down in the notebook—everything. I wrote down every name, every sign I saw, every conversation I heard, every inspiration that I had, every quotation. It all went down.

And I still do that just as methodically. I first did it out of the sense of anxiety, thinking what will this book be? What shape will it take? What's interesting? Even now I wonder. Is this anything? "What am I doing here?" is a question every traveler has to ask himself or herself.

So has my method changed? No, it's the same. I don't carry electronic apparatus. I don't have a tape recorder. I don't have a computer. I write everything in longhand, and I usually write it twice. I write it during the day in a small notebook and at night I expand it in a larger notebook. For 40 years that's what I've done. And then when I get home I type it out. I used to use a typewriter, now I use a computer. But it's all written, hundreds and hundreds of pages of notes, some of which I use, others not.

Your last few books seem to be focused on returning to places you've been or routes you've previously traveled. What draws you back to these places?

The compelling reason is to see how they've changed, because when you see how a place has changed, you can sort of understand how the world is changing. We all wonder what's going to happen in the future. That's just a normal human question—what's going to become of us? A great reason for returning to another country after 10 years or 20 years or longer is to see what has happened and how it's happened and why it's happened, too. Is it because of government? Is it because of a lack of money or an excess of money? Is it because of a health problem? Or whatever. It's not futurology exactly, but it's a way of seeing what's happening to the world.

In this book, what were some of the most surprising things you found, in terms of changing landscapes or people's activities or attitudes?

I didn't expect to see the improvements that I saw in Cape Town after ten years. I wasn't expecting the improvements I saw in some places—that surprised me, not gobsmacked, but heartened by it. Botswana is still a lovely, wild, and viable country. The idea that there is so much bush, and the Okavango Delta and the Kalahari Desert are still largely untraveled. The small population in Namibia—two million people in a country of that size is amazing. It's a vast country and that's [roughly half] the population of Boston and its suburbs. The other thing that surprised me was Angola. Here's this big country, but there are no wild animals. To be in such a large country in Africa with no wild animals is amazing.

You've spent your career traveling to some troubled places—Afghanistan, Iran, and Pakistan, and others—and you're also a native of Boston. How have your travels influenced the way you view those terror attacks in your hometown?

We need to remember the past. There were communities in Boston that supported the IRA in Northern Ireland. They were very sentimental about the Irish. They thought the Irish were fighting for their freedom, that's the way it was put: The IRA were freedom fighters. They were fighting against the Protestants and the British soldiers. And the method that the IRA used in Northern Ireland and in England was the nail bomb.

I lived in England for 18 years. What happened in Boston on that horrible marathon day was a very common occurrence in Belfast, even in London. Nail bombs killed several military bandsmen in Regents Park. They killed shoppers at Harrods. They killed people at Enniskillen. It was very, very common. And no one in Boston condemned it. And when Gerry Adams [the leader of Sinn Fein, the political arm of the IRA] came to Boston, he was marched around like a conquering hero.

The idea that our people are chanting "U-S-A, U-S-A" because a punk has been cornered and another one killed isn't really reason for rejoicing. Go see what's happened in the past, how other people have suffered. What the Tsarnaev brothers did was grotesque and appalling. But I lived in England when this was a common occurrence, and there was no sympathy from Boston.