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 1:39-45
"And Mary arose in those days, and went into the hill country with haste, into a city of Juda; and entered into the house of Zacharias, and saluted Elisabeth. And it came to pass, that, when Elisabeth heard the salutation of Mary, the babe leaped in her womb; and Elisabeth was filled with the Holy Ghost: and she spake out with a loud voice, and said, Blessed art thou among women, and blessed is the fruit of thy womb. And whence is this to me, that the mother of my Lord should come to me? For, lo, as soon as the voice of thy salutation sounded in mine ears, the babe leaped in my womb for joy. And blessed is she that believed: for there shall be a performance of those things which were told her from the Lord"