Celtic Studies discussion

Are there any scholarly books on Celtic Shamanism? I am really interested in this subject and would like to read some historical background on it.

The only scholarly work I can think of that might fit the bill is Emma Wilby's " The Visions of Isobel Gowdie: Magic, Witchcraft and Dark Shamanism in Seventeenth-Century Scotland " wherein she discusses the possibility of shaman-like practices within the confessions of Isobel Gowdie.

Other than that, I understood that in academic circles, shaman were only equated with the regions of Siberia.

Thanks! It was already on my to-read list, just need to make it a priority :-)

Tom Cowan is a practicing Celtic shaman who does workshops around the US. He has written a number of books.

There is Robert Graves The White Goddess: A Historical Grammar of Poetic Myth but those in the ivory tower reject it as being without any archeological proof.