Some of the earliest examples of written Welsh are going on display in Llandeilo from Friday.
The real book has been in Lichfield Cathedral for the last 1,000 years
A digital exhibition of the St Chad - or St Teilo - gospels will be unveiled by the bishop of St David's.
The gospels, which some experts believe were written in Wales in the 8th Century, are in Latin but have notes hand-written in Welsh.
The texts were removed in mysterious circumstances 300 years later and have been in Lichfield Cathedral ever since.
Scholars are divided over whether the St Chad Gospels originated in England or Wales.
The hand-written notes in Welsh in the margin include references to the Carmarthenshire village of Brechfa.
The notes are believed to be some of the oldest surviving examples on written Welsh.
But some experts believe the book is not Welsh at all and that it was loaned to Llaneilo from the Staffordshire area.
The "turning page" technology, developed by the British Library, was first used to help take an exhibition of the Lindisfarne Gospels back to the holy island three years ago.
Now it is hoped it will help bring visitors to west Wales.
The gospels were written and illustrated in the 8th century
Local vicar Rev Dr Peter Bement said: "We are excited at the prospect of displaying the gospels again in Llandeilo.
"This book is of huge importance in the cultural and spiritual history of Wales."
How the gospels came to leave Carmarthenshire is also a mystery. One theory is that they were stolen by light-fingered monks in the 11th Century.
The original script is too fragile to be displayed either in Wales or England.
Digital copies of the book have been made - thanks to the combined efforts of the parish of Llandeilo, Lichfield Cathedral and the British Library.
A version, including bi-lingual commentary, will go on show at St Teilo's Church in Llandeilo on Friday. A similar exhibition will go on show in Lichfield on Saturday.
Visitors to either display will be able to view digital images of the book and turn the pages using touch-screen technology.
The project has cost £100,000 and is the result of two years of careful planning.
The permanent exhibition will be opened in the tower of St Teilo's Church, the only surviving part of the Medieval Church, at 1100 GMT.
Professor Michelle Brown from the British Library will give a lecture on the significance on the 8th century masterpiece.