The Complete Roman Legions, by Nigel Pollard and Joanne Berry, is a fine, linear assembly of the legions of Rome from the Republican Period, the Imperial Age, and the Late Antiquity, by number. I found this book to be closer to what I wanted than Stephen Dando Collins's Legions of Rome (q.v.). The type is painfully small; the writing not so fluid and engaging. The illustrations, arrangement, and information about each legion, however, are all absolutely top shelf.
This is by no means a complete history of the Roman legions. It is a general overview and an introductory work. There are a few factual errors in the book, which detracts from its reliability. There are many other books available with more information and much greater accuracy, for example, "The Complete Roman Army" by Adrian Goldsworthy.
I liked it. A quick read that focused on the development of individual legions and their deployments & exploits. I enjoyed seeing how the different regions deployed and used their legions. I'd recommend.
This is an extensive and very thorough reference work about the Roman legions from the Manipular to Late Antiquity. It's a bit dull to read as a standalone, but provides great historical background for any legion you may encounter in other works.