If we all indeed come from Africa, then the very idea of Africa itself comes from the antique northern coast of that great landmass, where the cosmology is subtly different and where the inhabitants look north to Europe and southward at the Sahara. Here was the mighty civilization known as Carthage, which came as close as possible to reversing what we think of as the course of "history" and conquering Europe from Africa instead of the other way around. With its elephants and armies, and under the brilliant generalship of Hannibal, it penetrated all the way through Spain and France and down over the Alps onto the smiling northern plains of Italy. Not even the later Muslim conquests, which surged out of the Arabian Desert and along northern Africa and across the Strait of Gibraltar, ever got so far. After Rome took its revenge and deleted Carthage from the historical page a hundred and forty-six years before Christ—as I was told by the Tunisian archaeologist Neguib Ben Lazuz as we sat in the shadow of the magnificent Roman amphitheater of El Djem—it cast around for a name to call its new colony. The most imposing local people were the Afri, a Berber tribe in the northeastern quarter of what is now Tunisia. And the new province of "Africa," or "Ifriqiyyah," as its later, Muslim rulers were to call it, was sophisticated enough to give its title to a continent. There were Roman emperors—such as Septimius Severus—of African descent. In the eighth book of his Natural History, written in the first century a.d., Pliny the Elder made the observation, possibly borrowed from Aristotle, "Ex Africa semper aliquid novi" ("There is always something new out of Africa").

And so there is. If you look at the map now, you will see that Tunisia is like a little diamond-shaped keystone, its different facets constituting a frontline territory between Europe and Africa, North and South, East and West, the desert and the sea. It was from its gorgeous city of Kairouan—the oldest Muslim city in Africa—with its huge mosque built with the pillars of Roman and Carthaginian temples, that Islam was spread to the black sub-Saharan regions of Mali and Nigeria, and also northward to the Spanish region of Andalusia. And it is here that the crosscurrents between fundamentalism and cosmopolitanism, syncretism and puritanism, are being most acutely registered. From the northern tip of Tunisia on a clear day, you can see the shimmering Italian island of Pantelleria. Spanish and French and Italian coast guards regularly pick up Africans from as far south as Guinea who have traversed the interior to launch their craft across the Mediterranean. (One of these was picked up the other day, having attempted the perilous crossing with no more than an oil-drum raft and a G.P.S. navigation system. Give that man an entry permit! We require people with such initiative.)

On the other hand, so to speak, it was in Tunisia in April 2002 that an al-Qaeda suicide murderer drove a truckload of propane up to El Ghriba, the oldest synagogue in North Africa, a little gem of a building that has been the centerpiece of an ancient Jewish community—the largest in the Muslim world—that dates back two millennia. Nineteen people, mostly German tourists, were slaughtered.

I recently made my own visit to the place, which is on the island of Djerba, where Ulysses is said to have passed his time among the lotus-eaters. I was walking through the old ghetto, in which Arabs and Jews mix freely, when a series of bombs tore through cities in neighboring Morocco and Algeria, apparently to mark the fifth anniversary of this revolting crime. In January, there had been a firefight between Tunisian security forces and the newly named Al-Qaeda in the Islamic Maghreb, a gang formerly known as the Salafist Group for Preaching and Combat, which joined the bin Ladenists and has apparently been granted the bearded one's franchise. This poses a fairly stark choice. Will the northern littoral of Africa become a zone of tension, uneasily demarcating a watery yet fiery line between Europe and the southern continent? Or will it evolve into a meeting place of cultures, trading freely and cross-fertilizing the civilizations, as it did once before?

Tunisian society contains some of the answers to these questions. On the face of it, the country is one of Africa's most outstanding success stories. In the 2006–7 World Economic Forum Global Competitiveness Report, it was ranked No. 1 in Africa for economic competitiveness, even, incidentally, outpacing three European states (Italy, Greece, and Portugal). Home ownership is 80 percent. Life expectancy, the highest on the continent, is 72. Less than 4 percent of the population is below the poverty line, and the alleviation of misery by a "solidarity fund" has been adopted by the United Nations as a model program. Nine out of 10 households are connected to electricity and clean water. Tunisia is the first African state to have been accepted as an associate member of the European Union. Its Code of Personal Status was the first in the Arab world to abolish polygamy, and the veil and the burka are never seen. More than 40 percent of the judges and lawyers are female. The country makes delicious wine and even exports it to France. The Tunisian Jews make a potent grappa out of figs, which is available as a digestif in most restaurants. There were several moments, as I was loafing around the beautiful blue-and-white seaside towns or the exquisite classical museums and ruins, when the combination of stylish females, excellent food, clean streets, smart-looking traffic cops, and cheap and efficient taxis made me feel I was in a place more upscale than many European recreational resorts and spas. I remembered what my old friend the late Edward Said had told me: "You should go to Tunisia, Christopher. It's the gentlest country in Africa. Even the Islamists are highly civilized!"

But before I could be seduced into abject boosterism, I had a lengthy, not to say lavish, dinner with some of the country's academics and intellectuals and writers. The atmosphere in the restaurant was quasi–Left Bank Parisian, and I think I lulled them a bit by recounting some of the Davos statistics cited above. Then I added two more. Since its independence from France, in 1956, Tunisia has had exactly two presidents, the first of whom, Habib Bourguiba, became a "president for life" before being deposed for senility and megalomania. The current ruler, Zine El Abidine Ben Ali, will celebrate his 20th year of uninterrupted power this November. At election times, he has been known to win more than 90 percent of the vote: a figure that never fails to make me nervous. I have not met the man, but within hours of landing in the country I could have passed an exam in what he looks like, because his portrait is rather widely displayed.

Well, you can say for Tunisia that people do not lower their voices or look over their shoulders (another thing that has made me nervous in my time) before discussing these questions. But the conversation still took on a slightly pained tone. Was the West—that's me—not judging the country by rather exacting standards? To the east lay the huge territory of Libya, underdeveloped and backward and Islamized even though floating on a lake of oil, and, furthermore, governed since 1969 by a flamboyantly violent nutcase. ("We are the same people as them," said my friend Hamid, "but they are so much en retard.") To the west lay the enormous country of Algeria, again artificially prosperous through oil and natural gas, but recently the scene of a heinous Islamist insurgency that—along with harsh and vigorous state repression—had killed perhaps 150,000 people. Looking farther away and to the south, Sudan's fanatical and genocidal militia, not content with what they had done in Darfur, were spreading their jihad into neighboring Chad, extending a belt of violent Islamism across the sub-Saharan zone. Increasingly, Africa was becoming the newest site of confrontation not just between Islam and other religions (as in the battle between Christian Ethiopia and Islamist Somalia, or between Islamists and Christians in Nigeria, or Islamists and Christians and animists in Sudan) but between competing versions of Islam itself. Why pick on mild Tunisia, where the coup in 1987 had been bloodless, where religious parties are forbidden, where the population grows evenly because of the availability of contraception, where you can see male and female students holding hands and wearing blue jeans, and where thousands of Americans and more than four million Europeans take their vacations every year?

When it's put like that, who wouldn't want the alternative of an African Titoism, or perhaps an African Gaullism, where presidential rule keeps a guiding but not tyrannical hand? A country where people discuss micro-credits for small business instead of "macro" schemes such as holy war? Mr. Ben Ali does not make lengthy speeches on TV every night, or appear in gorgeously barbaric uniforms, or live in a different palace for every day of the week. Tunisia has no grandiose armed forces, the curse of the rest of the continent, feeding parasitically off the national income and rewarding their own restlessness with the occasional coup. And the country is lucky in other ways as well. Its population is a smooth blend of black and Berber and Arab, and though it proudly defends its small minorities of Shiites, Christians (Saint Augustine spent time here), Baha'is, and Jews (there is a Jewish member of the Senate), it is otherwise uniformly Sunni. It has been spared the awful toxicity of ethnic and religious rivalry, which makes it very unusual in Africa. Its international airport is named Tunis-Carthage, evoking African roots without Afrocentric demagogy. I still could not shake the feeling that its system of government is fractionally less intelligent and risktaking than the majority of its citizens.

However, it is not every day that you can go downtown to a university that is attached to a mosque—in this case the Zitouna, or "Olive Tree," mosque, with an old library housing thousands of ancient texts—and sit with a female professor of theology. Mongia Souaihi cheerfully explained to me the many reasons why the veil is not authorized by the Koran and why she is in danger for drawing this conclusion in print. "The fundamentalists from overseas have declared me to be kuffar—an unbeliever." This I know to be dangerous, because a Muslim who has once been declared to be an apostate is also a person who can be sentenced to death. "Which fundamentalists? And from where overseas?" "Rachid Ghannouchi, from London." Oh no, not again. If you saw my "Londonistan" essay, in the June Vanity Fair, you will know that fanatics who are unwelcome in Africa and Arabia are allowed an astonishing freedom in the United Kingdom. The leader of Ennahda, the outlawed Tunisian Islamist group, the aforesaid Mr. Ghannouchi, was until September 11, 2001, allowed to broadcast his hysterical incitements into Tunisia from a London station. "Almost everything we have worked for in this country among the young," I was told by Mounir Khelifa, a highly polished professor of English, "can be undermined by any one of a hundred satellite stations beamed into our society." I thought perhaps he was exaggerating, or perhaps feeling insecure. The Tunisian authorities sometimes give the same impression by hovering around in Internet cafés trying to invigilate what sites people are clicking on. In a society where satellite dishes are everywhere, this looks crude and old-fashioned.

So Tunisia's achievements, though real enough, are fragile. When the terrorists target tourists, they pick the economy's most vulnerable spot. (The Djerba atrocity had a real effect on that year's overall figures.) But, of course, they also isolate themselves, first by creating poverty and unemployment and second by violating the inflexible laws of Muslim hospitality. So this is the edge of uncertain awareness on which an outwardly happy and thriving society is poised. Some way to the south of that Roman amphitheater at El Djem, you begin to hit the Sahara. It was in this imposing dune landscape that Star Wars, Raiders of the Lost Ark, and The English Patient were filmed. It is also here that the desert ceaselessly, mindlessly, but somehow deliberately tries to move northward. Its rate of progress is uneven, and varies from country to country, and when you do see the Tunisian Army it is often helping in measures—of planting and irrigation—to stave off the remorseless encroachment. An enclave of development, Tunisia is menaced by the harsh extremists of a desert religion, and ultimately by the desert itself. As with everything else in Africa, this is not a contest we can view with indifference.

Christopher Hitchens is a Vanity Fair contributing editor.