Of all the pivotal dates in Western history – 1492, 1776, 1914 – one of the most important, if least immediately recognizable, is 216 B.C. That was the year Hannibal, the brilliant Carthaginian general, annihilated the Roman army at Cannae in a battle still studied by soldiers today. The debacle left Rome defenseless and raised the serious prospect of its complete destruction; according to the historian Livy, one of Hannibal’s officers told him that if he marched on Rome immediately, he could dine on the Capitol in five days. It was a moment when the entire course of history hung in the balance: If Carthage had defeated Rome in the Second Punic War, there would have been no Roman Empire, no Roman Catholic Church, no Europe as we know it.

Instead, for reasons that are still debated, Hannibal delayed, giving Rome the chance to recover its forces and rethink its strategy. Cannae turned out to be the high tide of Carthage’s fortunes. Eleven years later, after cutting a swath of fear and destruction across Italy, Hannibal would be compelled to take his army back to North Africa and defend Carthage against a Roman expeditionary force. After a long series of humiliating defeats, Rome had finally found, in Scipio Africanus, a general equal to Hannibal in daring and skill. When the two commanders met face to face at Zama, Scipio was the victor, and Carthage now lay as defenseless as Rome had earlier. Never again would Carthage threaten Roman supremacy. A half century later it was razed to the ground, the victim of Rome’s unchecked ambition. Today, Europe and much of the world speak Romance languages, while not a single document written in Punic survives.

The century-long contest between Rome and Carthage for control of the Mediterranean basin has always been a favorite subject of military historians. We know about the three Punic Wars in remarkably thorough detail, thanks to the surviving works of Polybius, who was present at the destruction of Carthage in 146 B.C., and of Livy, who wrote during the reign of Augustus, some 200 years later. As a result, we can track the contest on all its levels, from geopolitical strategy down to battlefield tactics. Aside from its inherent interest and its historical importance, the story also has clear contemporary resonance as an object lesson in the perils of great-power politics.

That lesson gained special urgency during the Cold War, when the clash of Rome and Carthage, like that of Athens and Sparta in the Peloponnesian War, seemed to prefigure the rivalry between the United States and the U.S.S.R. That was the context in which Sir Nigel Bagnall wrote “The Punic Wars” (Thomas Dunne Books, 368 pages, $29.95), and it had already begun to change when the book first appeared in Britain in 1990.

Its publication 15 years later in America, in a unipolar world where asymmetrical warfare is the new challenge, is thus distinctly untimely. Bagnall himself died in 2002 after a distinguished military career that saw him rise to become a field marshal and chief of general staff in the British army. But if “The Punic Wars” now seems less immediately relevant – and certain passages, such as Bagnall’s suspicious analysis of Mikhail Gorbachev, are positively obsolete – it is still a fine work of military history and a lucid guide to the subject.

As one would expect of a professional soldier, Bagnall was not interested in viewing the Punic Wars through the lens of economics or culture. (He is briskly dismissive of Marxist historians who see it as a simple contest for manpower in an age of slavery.) Instead, he takes the accounts of Polybius and Livy – supplemented by a few later ancients and interpreted by modern historians – and synthe sizes them into a clear narrative, using the concepts and vocabulary of modern warfare. His focus is on diplomacy, strategy, and above all operations and tactics – the practicalities of how troops got to the battlefield, and what happened once they got there.

The three Punic Wars each ended with a Roman victory, but the first two, at least, were close-run things. Carthage, founded by Phoenician settlers near the site of modern Tunis, led a maritime and commercial empire in the western Mediterranean, dominating Spain, Sicily, Sardinia, and much of North Africa. Rome, in the centuries leading up to the conflict, had established a land-based military empire in central and southern Italy, subduing first her Latin neighbors and then the Gauls to the north and the Greek colonies to the south.

The clash of these rising powers was probably inevitable, but the actual cause of the First Punic War, in 264 B.C., was trivial and almost accidental. The Sicilian city of Messana, threatened by Greek Syracuse, had put itself under the protection of Carthage, which controlled the western part of the island. But the city’s ruling clique decided it would be better off under Roman suzerainty, and appealed to Rome for a garrison. The Senate agreed to this, seemingly unconcerned that it would lead to a conflict with Carthage.

“There was no reason for these two powers to have become embroiled in a major and costly war,” Bagnall writes. “The fact that they did so, and over such a minor and unworthy cause, was unequivocally the fault of the Romans.” This leads to a strategic lesson: “The Romans saw an opportunity to advantage themselves, and … because they saw that the Carthaginians were unprepared militarily they succumbed to this temptation.” Deterrence, Bagnall reminds us, is only possible from a position of strength.

Once war began, it was needlessly and bloodily prolonged by Rome’s lack of a definite strategy. Rome dispersed its forces, fighting now in Sicily, now in Sardinia, now in Carthage itself, but with no clear aim in view. Only when the Romans decided to make Sicily their priority and to concentrate their naval and land forces on the Carthaginian bases in the west of the island did they bring the war to a successful conclusion. Again, Bagnall finds a lesson, one that is especially relevant in the age of Vietnam and Iraq: “Policy was determined by the sword and a major military campaign was entered into without any clear political objectives, and therefore with no strategic objectives either.”

The Roman victory gave way to 20 years of simmering hostility, which flared up again in the Second Punic War, in 218 B.C. These were, to quote one of Bagnall’s chapter titles, “The Epic Years,” when Hannibal used his tactical ingenuity to gain a series of stupendous victories. But they were not quite enough to destroy Roman supremacy in Italy. With its powerful base intact, Rome could eventually project enough force to sweep Carthage from all its Mediterranean possessions. When the war ended with Carthage’s abject surrender in 201 B.C., its days as a major power were finished.

This meant that the Third Punic War, in 149 B.C., was a brief and, in Bagnall’s view, inglorious affair. Rome seized on Carthage’s violation of the peace treaty to accomplish the total annihilation of its now-powerless rival, obedient to the vengeful exhortations of the stern Cato: “Cartago delenda est” (“Carthage must be destroyed”). And so it was, after a treacherous negotiation in which Rome demanded its complete disarmament, then proceeded to assault the city anyway. The fields were sown with salt, the population sold into slavery, the temples and libraries destroyed; nothing remained of Carthage but a name. And, of course, the story of the Punic Wars, which find in Sir Nigel Bagnall the latest in a long line of skillful expositors.