As the second book Luke addressed to Theophilus (see Luke 1:3), Acts may originally have had no title. The Greek manuscripts title it “Acts,” and many add “of the Apostles.” The Greek word translated “Acts” (praxeis) was often used to describe the achievements of great men. Acts does feature the notable figures in the early years of the church, especially Peter (chaps. 1–12) and Paul (chaps. 13–28). But the book could more properly be called “The Acts of the Holy Spirit through the Apostles,” since His sovereign, superintending work was far more significant than that of any man. It was the Spirit’s directing, controlling, and empowering ministry that strengthened the church and caused it to grow in numbers, spiritual power, and influence.