Hi Patricia, you could have a look at Malcolm Chapman's
The Celts: the construction of a myth
ST MARTIN'S PRESS 1992? (I don't have the ISBN right here)
Cha[pman examines many common misconceptions regarding the Celts, and how
we see them. Discusses the way in which a romantic and glamourisd image of
the Celts has been constructed in the last 200 years or so, and how this
still colours what we think about the Celts today. Fascinating stuff, a
bit heavy-going but well worth it.