Luke
Authorship and Audience
Before considering the author, it is important to note that Luke is part one of a presentation that continues into what we call the book of Acts (compare Luke 1:1-4 and Acts 1:1). As far as authorship is concerned, "Luke-Acts", as this combination of the two works is often known, was attributed to Luke by early church. Supporting evidence can be found in the book of Acts where the author, seventy seven times, uses the pronoun "we" to refer to himself and Paul (see Acts 16:10–17, 20:5–18, and 27-28:16). Thus, we know that the author of Luke-Acts was with Paul throughout some of his missionary journeys and Luke fits this description as he is mentioned in Paul's letters (Colossians 4:14, 2 Timothy 4:11, and Philemon 24) as a constant and faithful companion.
The particular audience of Luke-Acts is "Theophilus" ("θεόφιλος") as mentioned in Luke 1:3 and Acts 1:1. There is much debate as to the identity of "Theophilus", but there is nothing explicitly in the text. For the purpose of this summary, I will not delve into this any further as it enters the realm of conjecture and is not, in my estimation, essential to understanding Luke-Acts.
Date and Context
It is likely that the book of Luke was written sometime between 60 - 62 AD. Support for this conclusion comes from the fact that, in 1 Timothy 5:18, Paul quotes Luke 10:7 (and interestingly enough refers to it as 'Scripture'). As 1 Timothy was likely written around 65 AD, Luke would have to be finished by this time. Paul was imprisoned in Rome around 60 to 62 AD, so this would have been an ideal time for Luke to gather eye-witness testimony and compile his account. There are other historical events which are not mentioned in Luke-Acts like the destruction of the temple (70 A.D.) and the martyrdom of James (62 A.D.) which also supports the view that the book of Luke was likely finished by 62 AD.
Theme(s)
Christ is the Central Figure in World History. In his gospel account, Luke portrays Jesus as the one on whom the Old Testament prophecies and covenants depend and as the one who will change the future by establishing His kingdom and becoming a new, second Adam. Think of the history of the world as an hourglass, with Christ as the center. All history before Christ pointed to Him and all history after Christ stems from what Christ has begun. The long introduction to the book of Luke (1 - 4:13) is, in fact, a microcosm of the whole book. We hear prophecies from Mary and Zechariah that echo Old Testament passages and speak of how God is fulfilling the covenants He made with Abraham and David. We see from Christ's genealogy and temptation that Christ is, in a sense, a new Adam who does not fall into sin.
Christ Came to Save ALL Men. Put another way, Christ came to offer salvation to all types of human beings. Poor, rich, male, female, free, slave, 'religious', 'un-religious', Jews, Gentiles, Roman, the list goes on and on...
This is evidenced in the gospel of Luke as Jesus ministers to both Jews and Gentiles. We find him dining with Pharisees (wealthy religious leaders) and tax collectors (also wealthy, but known for their greed and regarded as traitors for serving Rome). Jesus heals a Centurion's slave and has His feet anointed by a prostitute. It is hard, nigh impossible, to think of a group of people from Jesus's time to which He did not minister.
Outline
0. Introduction [1 - 4:13]
A. Preface [1:1-4]
B. Introduction [1:5 - 3:20]
C. Identify and Validation of Jesus [3:21 - 4:13]
I. Ministry in Galilee [4:14 - 9:50]
II. Journey to Jerusalem [9:51 - 19:27]
III. Christ in Jerusalem (a.k.a. Passion Week) [19:28 - 23:56a]
IV. Christ Resurrected [23:56b - 24]
Observations/Notes
The genealogy from Jesus back to Adam in Luke 3:23-38 plays a critical role in the development of Luke's argument. First, the genealogy itself makes a connection between Jesus Christ and Adam. This is something Luke will continue to build on throughout the rest of the book of Luke and into Acts. Like Adam, Christ's first coming was the start of something new (which underscores the significance of Christ's coming in human history). Second, zooming back in on Luke 3 and 4, the genealogy at the end of chapter 3 sets the reader up for Jesus's temptation in Luke 4:1-13. When you start reading chapter 4, the key question is: "If Christ a 'new' Adam, will Christ fall like Adam did?". Luke uses the genealogy to flow into Jesus's temptation where we see that Christ did not fall like the first Adam and will, indeed, start something new. Notice how both Matthew and Luke use the story of Christ's temptation to further their, albeit different, arguments. This is not to say that either one of them is wrong or reading into the events of Jesus's life, but simply that Christ's fulfillment of complex Old Testament prophecy about Himself was complete and the significance of this for the future is tremendous.
Mary's beautiful prayer of thanksgiving offered after she got the news that she would bear the Messiah (Luke 1:46-55) is often called the 'Magnificat'. It bears a strong resemblance to Hannah's prayer in 1 Samuel 2:1-10 as both prayers praise God for considering the humble and reversing the broken state of things. Through both women, God demonstrates how He feeds the starving and sends "away the rich empty-handed" (Luke 1:53b); how He gives strength to the weak and weakens the strong; how he has "brought down rulers from their thrones, and has exalted those who were humble." (Luke 1:52).