Luke's gospel is the most objective and detail oriented of the four gospels. As a Greek Christian (the only non-Jewish writer of the gospels), Luke had a unique point of view. Luke was also the only gospel writer to have not met Jesus personally (both Matthew and John were among the 12 disciples, and Mark was a follower.) As a medical doctor, Luke took a chronological and scientific approach, focusing on Jesus' humanity.
The missive is directed to "Theophilus," either one man or a reference to Gentiles in general. (Theophilus means "lover of God"---Theos, meaning God; Phileo, meaning love.) His primary source of information was Paul the Apostle, but he also had access to several of the living disciples.
Luke probably wrote the book in about 60 CE (AD) from Rome.