Who was the author? The Holy Spirit inspired St. Luke, the beloved physician and co-worker of St. Paul, to write the book of Acts. Luke was a first-hand witness to some of the events the book narrates (the so-called "we sections").
What is the book? The book of Acts is the second of two works St. Luke wrote for Theophilus, possibly Luke's patron. The first told what Jesus began to teach and do from His birth through to ascension, and the second tells what Jesus after the ascension continued to teach and do through His Church, spreading the Gospel unto the ends of the earth.
Where was it written? Like the Gospel according to St. Luke, Rome may be the most likely possibility for the location where St. Luke wrote the book of Acts.
When was it written? St. Luke may have written the book right after the last events the book narrates (perhaps A. D. 63), since there are no references to significant later events, or St. Luke may have written the book 70 A. D. or later, with scholars explaining that no other significant events are mentioned because the events that are narrated serve St. Luke's purpose as set out in his theme verse (Acts 1:8).
Why? One commentator gives as the main purposes of Acts the following: to present a theological history, to give a defense of the faith for the purpose of converting people to it, to provide a guide for the Church, and to show the triumph of Christianity in the face of bitter persecution.
How? The Divinely-inspired St. Luke can be said to accomplish these purposes with accurate historical detail, literary excellence, dramatic description, and an "objective" account that tells of failures and successes, divisions and harmony, differences and agreement, in short, the bad and the good.
For further reading on the book of Acts:
- Bruce, F. F. Commentary on the Book of the Acts: The English Text with Introduction, Exposition and Notes. Grand Rapids, MI: Wm. B. Eerdmans Publishing Co., eighth printing, 1971. (This is a more-scholarly commentary that I have in my library, one that is more-current than Lenski's work below.)
- Lenski, R. C. H. The Interpretation of The Acts of the Apostles. Minneapolis, MN: Augsburg Publishing House, 1934, 1962 printing. (Despite its original date, Lenski's is a generally-reliable Lutheran commentary. He mixes more technical matters with general interpretation, but most readers would probably find his commentary quite accessible.)