The Book of Luke is addressed to Theophilus.
The third of the Gospels is that of Luke. Luke was a companion of Saint Paul and he also wrote the Book of Acts. Both books are addressed to a man named Theophilus. We do not know who Theophilus was; the name means "lover of God" so it may be a title rather than a name. Theophilus may also have been a Roman official as he is referred to as "most excellent", a term used elsewhere to describe Roman officials.
Luke was a Greek from the city of Antioch in Syria, and he is the only Gentile author found in the New Testament. His Gospel is intended to strengthen the faith of Gentile Christians; especially Greeks. He also wants unbelieving Greeks to hear about Jesus and come to believe in Him.
Luke 24:50-53
"And he led them out as far as to Bethany, and he lifted up his hands, and blessed them. And it came to pass, while he blessed them, he was parted from them, and carried up into heaven. And they worshipped him, and returned to Jerusalem with great joy: and were continually in the temple, praising and blessing God. Amen"