Author Peter Williams says that writing a commentary on the book of Acts has been a thrilling and exciting experience. Without Acts our knowledge of the history and progress of early Christianity would be greatly diminished and we would know nothing of the work of the Holy Spirit in the Church or how the world is to be evangelised. The aim of Luke, the writer of Acts, was to show how the church fulfilled the words of Jesus: "You shall be witnesses to me in Jerusalem, and in all Judea and Samaria and to the end of the earth". In a series of vivid images we see Peter preaching in the streets of Jerusalem, Philip preaching to the Samaritans and Paul travelling all over the Mediterranean world winning the Gentiles for Christ and finally establishing Christianity in Rome itself. Acts is both inspiring and challenging and has much to teach us about reaching people with the Gospel in our own day.