This looks like a must-have if not a must-read kind of book.
Having been in a museum of Celtic artifacts, this one, as a matter of fact, I can tell you--the Celts were like everyone else the Romans conquered. They had their own culture, their own achievements, their own masterful ways about them, and the Romans simply absorbed it all and took credit for it.
In particular, Robb notes that the Celts had to have had their own system of roads. If you look at the wagon, pictured in the burial chamber at Hochdorf, you can clearly see that the wheels would not have survived more than a country mile on uneven ground.
Graham Robb is helping to prove that the Romans were history's best example of what plagiarism and stealing and appropriating things can do for an empire.