Although this book has been published for some years, on reading through the reviews here I was struck by the praise heaped on this 'author'. I have commented elsewhere on the review by Aaron Thompson (who has hit the nail right on the head) and I do not want to repeat myself overmuch. I will be brief, in attempt to counter the somewhat one-sided view of Dando-Collins' output (I find it difficult to dignify what he writes by referring to it as 'work').
Briefly, this person's books are mostly made up. I do not believe that he has researched any of this. There are major errors, omissions and mistakes throughout. In a nutshell, he doesn't know what he's talking about. Example: he claims that legions were enlisted in 'mass intakes' (not true - only refers to Republican legions in the early years of Rome) and that battle losses were not replaced, so at the end of their '16-year' service, they would be seriously understrength. These were the crack troops of the Empire! Most of these legions were originally the product of the civil wars that eventually (via Caesar, Pompey & Marcus Antonius) brought Augustus to power. If the legions were re-raised at such intervals it would amount to replacing a sizable fraction of the army's men all at once. There is NOT ONE SHRED OF EVIDENCE FOR THIS PRACTICE. NOT. ONE.
A number of reviews here have stressed that the book 'reads very well', or is 'an exiting read'. I think if you buy this volume (and the subsequent efforts penned by SDC) you will not get anything like the correct impression of the history of the legions of Rome. It doesn't matter how well it reads if the information you are getting is WRONG. If you really want to find out more about this subject, try these works: (1) "The Making of the Roman Army from Republic to Empire" by Lawrence Keppie, (2) "The Roman Imperial Army" by Graham Webster, (3) "A Companion to the Roman Army" (ed. Erdkamp), (4) "The Complete Roman Army" by Adrian Goldsworthy, (5) "The Imperial Roman Army" by Jan le Bohec (English translation available), (6) "Roman Fortresses & Their Legions" (Ed. Richard Brewer) and (7) "Legions & Veterans", also by Lawrence Keppie. If you also want to see what the true origins, history, movements, campaigns and service of the legions was, try finding the BAR title "The Positioning of the Roman Imperial Legions" (BAR International Series, No.1458) by Jerome H. Farnum. I seriously doubt that Stephen Dando-Collins owns a copy of this or any of the others come to that!