This is the first book by Dando-Collins I have read, and I will not read another. It was apparently written for popular appeal, particularly with it's emphasis on how a legion saved Paul of Tarsus. That said, it was a pleasant read for an evening or two, depending upon one's reading speed. He fairly accurately depicts life in a legion and the events covered by his book. I would recommend it to someone who is not a scholar in Roman History.
The title is misleading in that the 3rd Gallica Legion was formed by Pompey in Gaul about 65 BCE, fought for Pompey against Caesar, surrendered to Caesar and was disbanded. The Legion was re-constituted by Caesar in 49 BCE (legionnaires served for 16 years) again with Gauls, fought at Munda for Caesar, and following Caesar's assassination, transferred its allegience to Mark Antony, It took part in Antony's invasion of Parthia in 36 BCE, was reconstituted again in 33 BCE with Syrian enlistees, then deserted Antony's cause for Octavian in 31 BCE. The enlistment periods were lengthened to 20 years, and by 58 CE, had been refilled with new enlistees four more times from Syria. This was when the events with Paul took place, and then after a further refilling, the Legion declared for Vespasian in 69 CE and materially aided him in achieving the throne by defeating Vitellius's troops. So why did the Author choose the emphasis on Mark Antony? One can only surmise it was due to Antony's name being familiar to the possible purchasers of the book.
The author's use of modern place name and modern terms for Roman ranks was really jarring. Calling Mucianus a Field-Marshal was really too much. A simple chart of ranks and their modern equivalents (if any) was all that was necessary. One could argue that a Legion was more akin to a modern Division (albeit much smaller) than a regiment, but such things are hardly important once the reader accepts the size, role and resources of the ancient formations. The author really stretched my credulity by using terms like lieutenant, captain, major, colonel, etc. Plus, he should know that there is no field-marshal rank in the American military. Also, using modern terms like "under fire" from arrows, javelins, slinger bolts, etc, misrepresent ancient reality. Treating modern readers like children who would be unable to understand any military terms other than those in use today (particularly when the reader is likely not to have served in the military) was insulting to say the least.
A final criticism was the author's naming convention. When he mentioned that joint emperors Balbinus and Maximus were killed by the Praetorian Guard (why not say Palace Guard?) in 238, I crossed out Maximus in my book and wrote "Pupienus." Unsure as to why the author said "Maximus", either the son of Maximinus Thrax, Caesar from 235-238, or Maximus Magnus, emperor from 383-388, I checked the full name of Pupienus. It was Marcus Clodius Pupienus Maximus, known to us as Pupienus. Calling Pupienus "Maximus" would be like calling Marcus Aurelius "Verus" since his full name was Marcus Aelius Aurelius Verus. And, of course, his co-emperor was Lucius Verus, full name Lucius Aelius Aurelius Commodus. So my recommendation to the author is to stick to Roman terms and classical naming conventions.
The author's lists of sources was excellent, although I would have been somewhat more critical of Cassius Dio (Dio Cassius). As can be seen from the list, ancient sources are few and have to be supplemented with numismatic and archeological evidence. His modern bibliography was equally good, but for readers in the dark about Roman individuals of importance I would recommend Diana Browder's "Who Was Who In The Roman World."