Nice books jonS
The mighty Stubob turned me on to Barnatts Peak book, it's a cracker, a classic in the 'alternative archaeologies' genre.
I have a copy of Giot's 'Mehirs et Dolmens' lovely B&W pics but with a French text, for a good English language guide to Britttany, Briards big yellow 'The Megaliths of Brittany' is excellent.
Robert Harris's 'Walks in Ancient Lakeland' is another lovely book, that fella loves his prehistory, I've road-tested his book to a number of sites and it really works. For Cumbria I'd also recommend Ray Setons's 'The reason for the stone circles in Cumbria' it's an odd little book written mainly from the dowsing perspective but the plans are excellent and he also provides a good guide for DIY surveying.
cheers