This book actually will tell you quite a bit about what is known about the ancient Druids: rather little, actually, and much of the evidence admits of many interpretations. Not that that stopped anyone from confidence. Which you will learn about in rather more detail, because it is the main subject of the book: the fascinating subject of what modern people have done with the idea of Druids. The ancient Druids are brought to explain what, if anything, actually substantiates the various types of druids, which gives it another interest, in watching how evidence can be put together, and picked apart, in support of various historical theses. It also discusses the evolution of ideas about pre-history, including how the Druids came to be viewed as the latest of pagan religions in Britain, but also in the context of discussing the types of treatment the Druid has gotten, over the centuries.
The Patriotic Druid, who encourages his countrymen in resistance to the invaders --the Romans, of course. Oddly enough, there are only a couple of references to Druids doing this, both in Tacitus, and neither one particularly reliable. Julius Caesar writes about Druids when discussing the customs and practices of Gaul, making them out as extremely important figures, but when he writes about his actual conquests, he never even mentions them. Odd. No one's come with a good explanation for that. But that didn't stop various early modern figures in Germany and France from using them as patriotic inspiration, and later British ones, which can feature both a unified patriotism, or a separatist one, in Scotland, or Wales, or England at different times, though not Ireland. Incidentally -- if you thought that the Druids weren't in Germany, you were right.
The Wise Druid. Alluded to in ancient writings, by people far off from the Druids. Put through some interesting convolutions by people trying to retrieve the wisdom of people who left no writings.
The Green Druid, the fellow who lived in harmony with nature and had a special association with trees. Found in some Roman writings, where it appears to be a way of showing what savages they were. A generation or so after writers didn't mention any such connection; perhaps persecution had driven them to this. On the other hand, writers who ran with this generally portrayed it as a fundamental trait.
The Demonic Druid. The monster of human sacrifice. This one, actually, there's a good bit of evidence for. Unfortunately, it's evidence of very dubious quality, being not only at least second hand but from the hands of people with obvious motives to slander them. And even it has been vastly exaggerated in the hands of writers out to write sensationally. Roman writers agreed that the Druids used criminals as sacrifices, and some said that lacking enough, they would use the innocent as well. Sensationalist writers assumed that they had a natural preference for the innocent, especially women and children. This chapter also delves into the archaeological evidence, since it's the only Druid who could be supported -- or undermined -- by such evidence. Which can, in fact, go either way.
The Fraternal Druid. Which actually has no roots in the past at all. Clubs and associations that used the name Druid.
The Rebel Druid. If there was one thing certain about ancient Druids, it was that they were part and parcel of their societies. Nevertheless rebels and eccentrics have frequently taken up the name as part of their revolt against society in general.
He concludes with some admitted speculation about what paths the notion of Druids might take in the future..