The period after the death of Augustus is often seen as the period of the 'Pax Romana', a relatively peaceful time in which the Empire didn't expand in any significant way. This book helps to remind us that the 'peace' only really applied to Rome itself, and even then outside the periods of civil war. Warfare was actually the normal state of affairs on the borders. The two maps of the Empire included clearly show this, with conquests in Britain, the Middle East, Anatolia, North-west Africa, central Europe and the Balkans in the period between 27 BC and c.200 AD. This was the period of the Jewish Wars, the Dacian Wars, the conquest of Britain, the largely defensive wars of Marcus Aurelius and a series of wars with Parthia (along with several periods of civil war and a number of internal revolts).
As well as charging the progress of Rome's wars and expansions in this period, Campbell examines the reasons behind them. These range fro the need of new Emperors to gain a military reputation, changes in allied kingdoms, and even on occasions areas conquered to defend against aggressive neighbours.
One slight oddity is that the book keeps the standard chapter headings for this series, which are really designed for single specific wars (background, outbreak, fighting, end of the war), when what we have here is a long series of separate wars. Fortunately this doesn't affect the text in this case. The title is also a little misleading - Rome had already 'risen' by the start of this period, but the 'Gradual Expansion of the Roman Empire' perhaps wouldn't have made such a good title (I wonder if a ;Fall of Imperial Rome is due to follow?)
About half of the book covers the actual fighting during this period. Here we see the main weakness of the Imperial succession - even moderately able Emperors could be dangerous if they felt the need to gain a military reputation, with some of the less military of them collecting a vast array of acclamations as 'Imperator'. Worse was the danger of the Imperial succession, where a disputed succession could lead to civil war, and even a disinterested Emperor could cause a series of crises on the borders.
This is a good account of a period that saw near-constant warfare somewhere on the massive borders of the Roman Empire.
Background to War: The Roman Empire in AD 14
Warring sides: Rome and her enemies
Outbreak: An uneasy peace
The fighting: Extending the Empire
Portrait of a soldier: Gaius Velius Rufus
The world around war: Travels in an unarmed province
Portrait of a civilian: Dio Cocceianus 'Chrysostom'
How the war ended: Neglecting the empire
Conclusions and consequences: A Changing Empire
Author: Duncan B Campbell