The book of Acts is an important book for understanding the actions of the apostles, mostly Paul and Peter, after Jesus's ascension into Heaven. It is an important book in understanding how we can be directed by the Holy Spirit and the role of Jesus' lessons in our lives. This is the story of Christianity's beginnings and how evangelism played a role in the spread of faith around the world. It is widely believed that the book of Acts is the second volume in Luke's gospel. While the first volume was what happened while Jesus was here on earth.