The Secret Country is the title, its written by Janet and Colin Bord, published by Paladin Grafton Books. I have had this book for some years but it reads sort of like a tour guide to "the ancient sites of the British Isles - standing stones, stone circles, henges, symbols, hillforts, burial mounds etc.
This book tells how "ancient sites of all kinds can be found to align. The sites forming such an alignment can be any combination of any of the following: stone circles, stones rows, standing stones, henges, cromlechs, hillforts, burial mounds (barrows, tumuli, cairns, etc.), ancient settlements, any other pre-Roman sites, also pre-Reformation (and sometimes later) churchs and other religious buildings and in certain circumstances also moats, prominent hills, anciet trackways, ponds and crossroads. The minimum numbef of aligning sites needed before a ley can be tentatively established is disputed but the greater the number of points there are in a short distance, the smaller is the possibility of ascribing an alignment to coincidence.
Initially, ley-hunting is done on an Ordinance Survey map, using a transparent straight edge and a pencil."
"Some believe that ley lings marked an energy current which flowed through the earth and that various marks point along a ley, standing stones, stone circles, etc. were crucial in the build-up, storage and dispersal of this energy current."
The writer speaks of Fairies Paths being like the Irish version of Ley lines.
I don't recall where I got this book but its a book printed in the UK, I may have purchased it in the UK. It was printed in 1986.
I would check sources like the book section on Ebay or Amazon, Amazon sells used books as well.