Very little is known about Luke. The little we know is what we read about him in Paul's letters. In Colossians 4:14, we learn Luke was a physician. In Philemon 24, Paul lists Luke as one of his "fellow workers".
Luke is best known as the saint that one of the Gospels is attributed to, as well as Acts of the Apostles. Both were written to Theophilus, a young gentile who had recently joined the Christian Faith. Luke writes to Theophilus so that he might "know the truth concerning the things about which" he had been taught (Luke 1:4).
Luke is a great reminder to us of our responsibility as Christians. We are all called to help raise up the generation after us to know what it means to live as a follower of Christ Jesus. Luke is an example to us of how to help bring up those who follow us so that the story of Jesus can be passed on from generation to generation for all time.