Dr. Luke wrote his gospel at around the same time as Matthew (early 60s), similar to how Armageddon and Deep Impact came out at roughly the same time.
Luke was not a Jew nor an acquaintance of Jesus (that we know of), but he traveled with Paul’s posse around the Mediterranean. Trained in medicine, Luke was also a historian, and his goal in writing his gospel account (and the sequel: Acts – This Time it’s Personal) is to provide academically rigorous historical credentials for the gospel story. As such, his version is the most thorough of the four. To Mark’s AP item and Matthew’s research paper, add Luke’s complete history.