The term 'Acts of the Apostles' refers to a book in the New Testament of the Bible. It is the fifth book of the New Testament and is written by Luke, a companion of the Apostle Paul. The book chronicles the spread of Christianity from the ascension of Jesus Christ to the spread of the gospel throughout the Roman Empire. It also details the missionary journeys of Paul and his companions. The book is traditionally abbreviated as 'Acts' in four letters.