The library said that the irreplaceable 18th Century book, annotated by Jonathan Swift, was recovered in Dublin after being stolen in an armed robbery in December 1999. Other stolen material not yet recovered includes miniature books, medals and manuscripts, known as a Papal Bull, of Clement XII.
The prized Swift edition will put back on display alongside other recovered works when the 230-year-old library is officially opened after restoration work in October.
The book was handed over in Dublin to the Dean of Armagh and keeper of the Library, the Very Rev Herbert Cassidy. He paid tribute to the "painstaking" work of Gardaí in co-operation with the RUC which had brought about this result.
Church of Ireland Primate and Archbishop of Armagh Dr Robin Eames, who is also chairman of the governors and guardians of the library, said that he was delighted at the safe return of the building's treasure.
