The legions of Rome were among the greatest fighting forces in history. For almost half a millennium they secured the known world under the power of the Caesars. This pioneering account gathers together the stories of each and every individual legion, telling the tales of their triumphs and defeats as they policed the empire and enlarged its borders.

- Part I examines the legions of the Republic from Rome's foundation to Caesar's legions and those of Octavian and Mark Antony in the civil wars.

- Part II provides "biographies" of all forty-five legions from 31 BC to the third century AD.

- Part III discusses the legions of Late Antiquity in the declining years of Rome's hegemony.

- Datafiles on each legion and detailed box features on major topics complement the text.