This book absolutely brims over with illustrations, making it an excellent addition to any Druidic shelf. While I disagree with some of Ms. Green's statements (such as saying the Celts were basically illiterate - an argument convincingly disputed by Peter Berresford Ellis, among others) and I am not comfortable with the summation of modern Druids comprising the end (making us all seem cookie cutter similar), I still believe this book should be read. The numerous illustrations I have already mentioned do much to show examples of things or places you may have heard of before, but were previously unable to picture mentally. At the end of the book is an excellent "travel planner" if you plan to visit some of the ancient sites associated with ancient Celts and Druids.
Green has solid Celtic studies credentials and her previous books, like the Dictionary of Celtic Myth and Legend (Thames and Hudson) were exemplary in terms of quality photographs and helpful bibliography. I therefore had, perhaps unfairly, high expectations for Green's The World of the Druids. Though there is a fair amount of text on each page, most of the emphasis is on the images and their captions. The captions often reinforce the impression that the non-artifact images created by artists like Gustav Dore and Fuseli are legitimate sources of data about historic druids, when they are at best sources of data about romantic nineteenth century presentation and imaginative views regarding druids.
Much of what Green has to say is speculation, presented as fact or scholarly hypothesis, like her ruminations on druidic prayer: "Druids and their peers would have conducted solemn prayer rituals for the whole tribe or community on important occasions. Lesser priests might lead small communities in prayer, and the head of the household perhaps led private family prayers" (32). Unfortunately, there really isn't a lot of data one way or the other about druid praying in the pre-Christian era. Green makes such assertions without referring to sources or even using the resources of comparative religion as support. There are a number of similar problems.
Green is at her best in The World of the Druids in her discussions of archaeology, and at her worst in discussions of myth and literature. Her chapter on sacred places is particularly well done, but not by itself worth the price of the book. She does include a brief survey of modern druid groups' beliefs and a directory of neo-pagan druid groups, but readers would probably do better to use the web to find Neo-Pagan druid resources since addresses and contact people change so quickly. The gazetteer of Celtic museums in the back of the book is a very useful list, and quite nicely done, though I wish her bibliography had been a bit more extensive.
I think in Green's efforts to relate to a new audience, specifically Neo-Pagan and new age readers, she missed her target by "dumbing down." Green would have done better to have written a well-bibliographied introduction to druids along the lines of The World of the Celts or her Dictionary of Celtic Myth books. I think that Neo-Pagan readers can readily find enough unscholarly material about druids; what they need is access to well-researched and cited books directing them to additional sources. Unless you already have Piggott's The Druids, and Green's World of the Celts, I'd give The World of the Druids a miss.