The Veil of Isis: Now Available!by Styxhexenhammer666
If it's folklore you want it's folklore you get! This work starts out as a slightly dry, historical look at the druids, before becoming almost a completely different work which combines a bit of Masonic and Catholic pagan symbolism (the kind you find on the 'weird' side of the internet) with then-modern folklore both in and out of the British Isles. Considering the dedication...
Celtic Mythology: Now Available!by Styxhexenhammer666
This particular book is a nice collection of linguistic lore and superstition related to the development of the Celtic people. Some of the content here is technically eugenic, proposing three separate ethnic groups with regards to the Celtic people.
It speaks of the divisions of Celtic culture (the bards, vates, and druids) and many other topics, and gives not just a broad...
Celtic Religion: Now Available!by Styxhexenhammer666
This little work is a fairly brief primer on the basics of Celtic spiritual systems. It goes into the division of the Druid priesthood in the pagan era, among other things, and correlates the development of the religious beliefs there with the advancement of contemporary culture. Altogether it's a very good work, although a few of the tenets it espouses have been largely forsaken...