"King's focus is on the wheel of the Celtic year with its cycle of four celebrations.... King describes the religious underpinnings of the festivals, the functions of the Druid priests and bards, relationships to other mythologies, and the influence of historical assimilation and migration on what we know of Celtic myth."-- "Booklist. 256 pages, 30 b/w illus., 6 x 9 1/4.
Academic reading (even in regards to spiritual matters--and this book explores spiritual theories rooted in historical context) requires a lot of compartmentalizing. This is because you need to retain information while you seek another source; you need to be able to analyze sources critically (as King discusses himself); you need to be able to release information when those sources do not exist or do not withstand your scrutiny. If something sounds suspicious or strange, follow up. If something doesn't ring any bells, definitely follow up.
There is also the matter that context changes. New discoveries are made that rule out old, sometimes long-standing theories. When reading this book, it is important to remember that it is from the early 1990s. Many of the materials King was working with were becoming dated, even then. And, frankly, this is largely a book of theories. There is historical context included, because to understand a culture one must understand the world it lived in. Much of the historical information seems accurate: Several sources can validate the military history, and I've consulted a few of my friends who are more privy to Roman history, and they didn't see many problems with it.
The problems with this book come from taking his interpretation (and the common interpretation) of Celtic paganism as fact. He warns you in the introduction NOT to do this. My main problem with this book is the incorporation of the Wheel of the Year. While he makes a point of stating that not all cultures celebrated all equally (or that, frankly, we cannot know if they did or didn't), he neglects to emphasize the modernity of the wheel itself. While he does mention scholars who broke the wheel down into its eight components, I think he failed to deliver the warning that this is a modern interpretation. Were these times of year important for various but possibly-connected reasons to multiple cultures? Sure. Were they all interconnected and equally important? Doubtfully.
And that is my point. This is the sort of source one uses to get a general, although not necessarily introductory, grasp of a culture. It provides intermediate-level launching points for one to research, and I strongly suggest you do that research so that you have the intellectual background to come to your own conclusion about his theories.
This is one of the single worse books on Celtic/Druid history and culture I've ever read. The writing isn't organized as the author begins to write about certain themes, then detours and then returns to the original theme paragraphs or chapters later. Several chapters of this book could have been completely left out and not affected the overall picture that Mr. King paints for us about the Druids as he says so little about them. Writing some background about who and what influenced the Druids is fine, but Mr. King seems to focus on other cultures, peoples, and their achievements to the detriment of his stated subject. He writes about Pythagoras at great length and should have just written a book about him alone. He tries desperately to tie in the Druids to Pythagoras with no definitive evidence for it. There is not enough information on the Druids, their practices and culture to support several of the claims he makes about them as there is so very little known about ancient Druids. Mr. King even admits that modern Druidism is conjecture (due to the lack of a written Druid history). I think most of this book is conjecture as he writes mainly about the Romans and Greeks with a little Celt (and even less Druid) history and practice thrown in. What is mentioned about the Druids is only repeating what was already mentioned from the beginning of the book.
I'm impressed by John King in his success of unbiased theory. He uses classical sources to build upon some of his ideas, including Pythagoras. However, the bulk of his conclusions come from Celtic agriculture and the resources available to the Celts. King adds to the conclusions already made about Druids while clarifying misconceptions.
Considering it is a book stuffed with information it can be somewhat difficult to trudge through. King helps the reader along by maintaining a casual tone rarely found in history and speculative texts.