Gladius is an extensive, thematically organized look at the life of the Roman soldier, focusing on the long era Republican conquests around the Carthaginian Wars and the Christianization of the empire under Constantine.

Bédoyére draws from historical documents, archeological evidence, and primarily tomb inscriptions to depict a military world that was central to Roman society. After the Marian reforms, legionnaires were core parts of the administration of the empire, manning posts from lonely borders to dense trade hubs and doing everything that needed doing, not merely war.

The legions were both strongly standardized in terms of size, structure, and camp size, and also idiosyncratic in naming, command, and the attachment of auxiliary units of archers and cavalry. While centurions were veterans promoted from the ranks on the basis of experience, high officers were often inexperienced military tribunes drawn from the young men of the senatorial class.

This is a popular work (the author is a TV presenter, rather than a professor), which has the advantage of the writing being actually good. The thematic organization is well done. I particularly enjoyed the defeat-victory-atrocity triad of chapters, as well as looks at under appreciated elements, like the Roman navy, retirement, and side jobs.