The Gospel of Luke is one of four books in the New Testament that describe some of the life of Jesus Christ. The authors of the gospels wrote about different aspects of who Jesus was and what he did. Luke wrote this gospel for a man named Theophilus. Luke wrote an accurate description of the life of Jesus so that Theophilus would be certain of what is true. However, Luke expected the gospel to encourage all believers, not just Theophilus.
This book does not give the name of the author. Since early Christian times, most Christians have thought Luke was the author of both the Book of Luke and the Book of Acts.