I am a big fan of Osprey books and I have quite a few in my collection and find they usually provide all the information needed to research a model. This book by Ross Cowan is no exception, and it is a follow-up book to his work Roman Legionary, 58 BC – AD69, which was published in 2003 by Osprey.
The Roman Legionary in the prime of the Empire was a fine tuned fighting machine. Kept in shape by constant labor, such as building forts and roads, their universal training meant that Legions from opposite ends of the empire could fight alongside each other seamlessly. Each man knew his place and function in the battle lines.
This is not to mean that the Romans were unbeatable. There are several cases of Legions (Approximately 5000 men at full strength) being destroyed or vanishing during our time period. Also, with rebellious leaders trying to seize control of the Empire, it was not uncommon for Legion to face Legion in battle.