John Bowker is a professor of religious studies who has taught at the universities of Cambridge, Lancaster, Pennsylvania and North Carolina. He has written and edited many books on world religions including World Religions, God: A Brief History, The Cambridge Illustrated History of Religion, and The Oxford Dictionary of World Religions.Sonia Halliday specializes in aerial photography of historical sites, particularly in Israel and Jordan. She has been taking photographs around the world for 40 years.Bryan Knox has been a photographer for 25 years, specializing in such areas as wildlife and stained-glass windows.