The author of the Third Gospel and Acts of the Apostles is traditionally credited to Luke (Λουκᾶς), a companion to Paul, and affirmed in the writings of the early church writers. Although not named in either work, Luke is mentioned by name in Paul’s letter to Philemon 24 as one of Paul’s “fellow workers” (οἱ συνεργοί μου) and in Colossians 4:14 is called “the beloved physician” (ὁ ἰατρὸς ὁ ἀγαπητός) Moreover, although most of Acts is narrated in the third person, there are four sections where the author uses the first person plural, known as the We-Sections (16:10-17, 20:5-15, 21:1-18, and 27:1-28:16). These passages are thought to derive from Luke’s travel notes and are usually interpreted to suggest that he accompanied Paul in his second journey from Troas in Asia Minor to Philippi in northern Greece, on Paul’s third journey from Philippi to Jerusalem, and Paul’s final journey from Caesarea to Rome.
The Third Gospel and Acts are meant to be read as a two volume set. They both are addressed to the same Theophilus. The ending of Luke’s Gospel and the opening of Acts reference the ascension of Jesus into heaven and the coming of the Spirit. They are both set in a consistent geographical and historical framework. Luke’s Gospel begins and ends with the Jesus-story in Jerusalem while Acts begins in Jerusalem and ends with the spread of Christ’s message outward all the way to Rome, the heart of the Roman empire. Moreover, Luke situates the life of Christ and the early church in both Roman and Palestinian events, such as the birth of Jesus (Luke 2:1-2), the beginning of Jesus’ ministry (Luke 3:1), and Jesus’ trial (Luke 23:1-5). And Acts depicts the formation of the early Christian church within world history, moving from Jerusalem to the rest of Judaea and Samaria (Acts 8:1) and Galilee (8:40, 9:31). From there, it spreads to Syria and Phoenicia (11:19), to the Roman provinces in Asia and Greece (e.g., 14:1; 16:11), and finally to Rome itself (28:14).
Fitzmyer, Joseph, ed. The Acts of the Apostles. The Anchor Bible. New York: Doubleday, 1998.