The 1,500-year book is believed to be the Gospel of Barnabas, which Muslims believe is the original gospel.
St. Barnabas is traditionally identified as the founder of the Cypriot Church, an early Christian later named an apostle.
Gunay said the leather-bound text, written on animal hide, could be an authentic version of the Gospel, which was suppressed by the Christian Church for its strong parallels with the Islamic view of Jesus.
He said Pope Benedict XVI had officially requested to see the book, which was found by Turkish police during an anti-smuggle operations in 2000.
In the book, Jesus is believed to have predicted the coming of Prophet Muhammad.
In one version of the gospel, he is said to have told a priest: How shall the Messiah be called? Muhammad is his blessed name', Gunay said.
And in another, Jesus denied being the Messiah, claiming that he or she would be Ishmaelite, the term used for an Arab.
Muslims believe in Jesus as one of the great Prophets of God and that he is the son of Mary but not the Son of God. He was conceived and born miraculously.
In the Noble Qur'an, Jesus is called "Isa". He is also known as Al-Masih (the Christ) and Ibn Maryam (Son of Mary).
As for his crucifixion, Muslims believe that Jesus was not crucified but was lifted up to heaven.
Muslims believe that Jesus will come back to earth before the end of time to restore peace and order, fight the Anti-Christ (Al-Masih Al-Dajjal) and bring victory for truth and righteousness.
The true followers of Jesus will prevail over those who deny him, misrepresent him and reject him.