A Disclaimer: I have a PhD in (Greek) Archaeology and thus, while I am generally unfamiliar with many of the specifics, I approach this book with a background in the subject matter. While I cannot detach this background from my review I can speculate on what I want to see in popular history/archaeology (and, spoiler alert, The Celts is largely it); ultimately, however, I have to admit that this book is not really for me, although I did enjoy reading it. Also, I read a paperback edition that does not appear to be on Goodreads, not the hardback edition to which this review is attached.
In The Celts: Search for a Civilization Alice Roberts sets out to explore the archaeological, historical, and linguistic evidence for "the Celts" and to understand what it is that we mean by that designation of an ancient (and modern) people. She is very clear about the difficulties of building historical narratives from archaeological evidence and the historical writings of completely different civilizations, difficulties that are well-known among archaeologists and historians but that don't seem to get as much respect as they deserve in popular historical discussions. She never quite says "this is not the case", but rather "while this could be the case, it is a bit of a leap (based on the evidence) to say so". While this might sound like Roberts never come to any conclusions, she is actually very willing to nail her colours to the mast regarding which hypotheses about Celtic origins she believes. I am not certain that I agree with her, but she certainly presents the evidence in such a way that it is both possible to see where she is coming from and possible to disagree. As the evidence for 'Celiticity' presented in this book shows, it would be dubious to discuss the Celts in any other way. They are something of an enigma, and Roberts does not shy away from saying so.
It is really only the style of the writing that I find off-putting. At times, it is what I can only describe as bombastic, as if aiming to give a sense of drama somewhat undermined by Roberts' professional approach to the evidence. It feels like it was inadequately adapted from the television series, where one might back such statements with swelling music and stunning visuals, to the book, where one does not. Similarly, Roberts describes certain meetings with archaeologists and discussions about their research in a way which might have narrated the video of her doing so in the show. Personally, I found this style a little off-putting to read, and would have preferred it to be more adapted to non-fiction book (i.e. not presented in dialogue). But I recognize that this preference is a personal one, and it might be much more welcoming to others than pages of text with references.
From an academic perspective, I have a few problems with Roberts' methodology, in that she never quite establishes how one identifies ethnicity archaeologically, particularly when it comes to ethnicity as a personal identity. That is to say that, while the book discusses at length markers that we might use, problematizes the evidence available, and ultimately settles on language as the central aspect of Celtic identity, Roberts does not delve very deeply into the question of how to understand 'Celticity' as a feature one attributes to oneself, as an identity that brings Gauls, Britons, and Galatians together (indeed, she even suggests that it does not), as opposed to something ascribed by others (whether contemporary or modern historians) or described by others (e.g. Caesar writes that the Gauls called themselves Celts, but does not establish how far the Gauls use this identity to link themselves to other groups). It is also, I would argue, a little dismissive of Tacitus to describe his work as 'propaganda' for the Roman elite, as fair a description as that may be of Caesar's works. Roberts' approach to the Mediterranean 'empires' is perhaps the weakest part of the evidence in the book, as she persistently refers to the 'Greek empire', which is not an historical entity. The 'Greeks' - almost as contentious a term as 'the Celts', if we are honest - were politically disparate for much of the period under discussion, and their regional and civic identities might actually provide a good parallel for the disparate, changing location and identity of the Celts.
But it is not the Greeks but the Celts who are under discussion, and Roberts goes into great detail about major evidence spanning centuries and a whole continent. Given that the book is quite short, she does so admirably and interestingly. I will certainly be delving into the further reading at some point. Furthermore, Roberts' openness about certain aspects of her methodology - and archaeological methodology in general - is exactly what popular archaeology (and history) requires. She admits where she moves from solid to speculative evidence, is unconvinced by certain evidence, and allows for others to disagree with her. She anticipates many (fair) criticisms of her work, aptly displaying how archaeology and history should work: debate, discussion, disagreement - but amicably. It is largely only those who hold too strongly to their ideas and will not be challenged that are the problem in historical studies.
In The Celts Roberts offers an interesting perspective on Celtic identity through antiquity to today. While I may not completely agree with her findings, I understand and respect her position on the evidence. I am also impressed that, in her "further reading", she anticipates the areas in which i disagree with her and provides a reference for an alternative viewpoint. It is good-natured scholarship that is very much what I would like the public to read about our discipline.