The longer it went on the more we thought that it had probably found its way into a private collection and would not be heard of for generations

Rev Herbert Cassidy Dean of Armagh

The book was handed over to the Dean of Armagh and keeper of the library, the Very Reverend Herbert Cassidy.

Speaking on BBC Radio Ulster on Thursday, Reverend Cassidy praised the "painstaking" work of the gardai in the Irish Republic and the RUC which, he said, resulted in "this happy result".

"There has been a criminal investigation ongoing since the book was stolen in 1999," he said.

"We are delighted to have the book back and we have looked at it very carefully to make sure it is all there.

"It has been very well looked after but we are delighted to have it back as the longer it went on the more we thought that it had probably found its way into a private collection and would not be heard of for generations."

The book was stolen from Armagh Library in 1999

The book was published in London in 1726.

"Swift himself used this particular volume and annotate it in his own handwriting, correcting the mistakes in preparation for the second edition, so that makes it interesting."

Other material also taken in the raid has still to be found, including miniature books, medals and manuscripts, known as a Papal Bull, of Clement XII.

Church of Ireland Primate and Archbishop of Armagh Dr Robin Eames, also chairman of the governors and guardians of the library, said he was delighted at the safe return of the book.

The library hopes to have it back on display along with other recovered books after building work is completed in the Autumn.