Roman Warfare, by Adrian Goldsworthy

What made Rome's legions so successful in the ancient world? Much has been made of their discipline, training, good equipment and well-organized logistical support. But these factors were not unique to the Roman military; other armies of that era shared these traits as well.

What gave Roman legions their edge was their flexibility and, as Adrian Goldsworthy explains in his authoritative book, Roman Warfare, their ability to adapt to almost any situation and defeat very different opponents, be they Hellenistic phalanxes, the Carthaginian navy, Germanic and Gallic tribes, or the Numidians. Roman units excelled at large pitched battles, but could also build massive siege works and even fight as marines.

But this still does not fully explain why Rome ultimately conquered formidable foes such as Pyrrhus and the Carthaginians and kept trying, again and again, to defeat the Parthians. Goldsworthy argues that Rome's savage, ruthless way of fighting, their refusal to admit defeat (even when a battle was lost), and their willingness to suffer heavy losses to achieve total victory were instrumental in their overall success.

After a Roman army was wiped out by Pyrrhus, leader of Epirus, Rome raised another legion and fought him again until they were victorious in 275 BC. Despite suffering multiple defeats at the hands of Hannibal, Rome did not accept peace terms - as other states would have done - but relied on its superior numbers to gradually wear their opponent down, and then defeated him decisively at Zama in 202 BC. With the Parthians, Rome never sued for peace, but fought them to a stalemate.

For the Romans, according to Goldsworthy, there were only two outcomes in war: either the opponent is totally defeated and becomes a subordinate ally or province, or Rome itself was destroyed. And because Rome would never surrender, and its opponents couldn't totally destroy her (until the very end, of course), Rome was almost always, ultimately, the victor.

Total defeat of the enemy was necessary because Rome did not want to see it rise again as a potential foe. This is why, Goldsworthy writes, Rome provoked the Third Punic War (149-146 BC) and obliterated Carthage as an independent political entity. They wanted to end that possible threat for good.

Coupled with Rome's uncompromising, relentless pursuit of victory was its ability to absorb newly defeated peoples into its ever-expanding community. Slaves were granted Roman citizenship once freed. Vanquished states not only became allies, but actively supported Rome in further conquests. Recently defeated Carthage, for example, supplied grain to the Roman legions battling Philip V in 200 BC. Philip in turn helped the Romans fight the Seleucids.

All this is covered concisely in Roman Warfare, detailing how legions changed in make up and battle tactics over time, from early Rome to the end of the Western Roman Empire. The volume comes with beautiful illustrations, photographs, maps, diagrams of principle battles and informative appendices. It's a must read for any ancient warfare buff.