Author/Editor: Chris McNab.
Title: The Roman Army: The Greatest War Machine in the Ancient World.
Publisher: Metro Books (New York).
Price: $12.95 (US).
This books was a compilation of different experts on the Roman army. It covered from the founding of Rome in 758 BC through the fall of the western Empire in 476 AD until the Muslim conquests in the 7th century AD.
Different sections were dedicated to the composition and tactics of the Roman army during each phase of its long history. Afterward, particular campaigns and battles were highlighted in detail. I found the Republic and late Empire fascinating reading.
I know the most about the late Republic and early Empire from my other readings. I used to be able to read Latin and survived it as an undergraduate student. I recognized the different Latin for soldiers and military units in the Roman army. However, it's has stagnated without constant use. I doubt I could sightread Caesar or Plinty if I tried. I had trouble translating Latin 20 years ago. I don't even want to try now.
However, the book is a solid piece of scholarship. If you're looking for what the Roman army was like when it waged war, The Roman Army is a good start. It has borrowed heavily from Osprey Publishing for its color plates of what Roman soldiers looked it.
The problem with Roman history is the amount of time covered. You really have to delve into a partial section of the Republic or Empire in order to really study it. Outside of reading classical text in their original language, I recommend a decent English translation of primary sources. If you're looking for information about the late Republic, I'd recommend Caesar Against the Celts if you can find a used copy of it on Amazon, Barnes and Noble, or a used book store.
Recommended for introduction to the Roman war machine. Though rather dry on some of the technical aspects of unit tactics.