The document titled 'Active Christianity: An Introduction' discusses the essence of active Christian faith, emphasizing total commitment to Jesus Christ and adherence to his teachings as fundamental. It details the historical development of Christianity, its major branches, beliefs, and the life and teachings of Jesus, who is regarded as the Messiah and central figure in Christianity. The document also highlights the role of Christianity in societal development and the current state of adherence globally, noting both growth in certain regions and persecution in others.