In certain sections of Acts, the author uses the first person plural in the narrative (Acts -17; 20:5-15; 21:1-8; 27:1-).
These are usually referred to as the we-sections and would indicate that the author of Acts accompanied Paul at these times.
 Regarding its location, it is generally agreed that Luke-Acts was not written in Palestine.
Other suggestions have included Caesarea, Achaia, Decapolis, Asia Minor, and Rome.
From these three occurrences, it is evident that Luke was a physician (Col ) and a companion of Paul (2 Tim ; Philem ).
It is more than likely that Luke was a Gentile, but he was not necessarily a Greek.The Gospel according to Luke exhibits several differences from the other Synoptic Gospels.For instance, Luke is the only Gospel to have a sequel, the Acts of the Apostles.This is remarkable considering the amount of attention he gets in comparison to John and Paul.The Gospel according to Luke was probably the last Synoptic Gospel to be written.Luke is the only one that would fit into this mold according to Paul's epistles.Externally, even the earliest manuscripts support the title "According to Luke" ().He also says that he cautiously examined everything from the beginning and this led him to write an organized account to Theophilus so that he might know the certainty of what he has been taught.It is obvious that Luke wrote to Theophilus, but who was Theophilus? Much of early church tradition also believed that Luke wrote this Gospel. The name Luke is only mentioned three times in the New Testament.