Acts is the book that reveals the history of the New Testament church. If the book of Acts was taken out of our New Testament, we would never understand the rest of it. Luke is the author of the book Acts. He was also the author of the Gospel of Luke. Luke and Acts together make up about 28% of our New Testament. The book of Acts is God's divine book on the subject of church history.
If we are ever to understand New Testament Christianity we must have knowledge of the beginning and growth of the church. The importance of the book of Acts is seen in the words of Acts 1:3. Luke spoke of those "To whom the Lord shewed himself alive after his passion by many infallible proofs, being seen of them forty days, and speaking of the things pertaining to the kingdom of God."
The common elements in all of the preaching throughout the book of Acts are: (1) Jesus fulfilled the prophecies of Old Testament, (2) Jesus is the Messiah, (3) He had a great miracle working ministry, (4) He was crucified as a sin sacrifice, (5) He was raised from the dead on the third day, (6) He now reigns as King of kings and Lord of lords, (7) He will come again, (8) The world will be judged by His word, (9) therefore, all men everywhere need to hear this message, repent of sins, be baptized for the remission of sins and serve God out of a heart of deep love.