This book is similar to Gladys Thompson's Patterns for Guernseys, Jerseys and Arans: Fishermen's Sweaters from the British Islands or Beth Brown-Reinsel's Knitting Ganseys but Domnick's book seems clearer and easier to adapt if you'd like to design your own "traditional" sweaters.
I particularly like (and will quote often) the Celtic blessing Ms. Domnick quotes toward the end of this book:
Blessing for a Handmade Garment
May you wear the garment to shreds!
May you wear the garment to tatters!
May you wear the garment
with food and music in every place.
As I would wish:
with a grace of the
(taken from: The Little Book of Celtic Blessings by Caitlin Matthews)