Gibson believes that four times in ancient history the Arab people united and poured out of the deserts to conquer other nations. The first is described in the Qur'an as the people of 'Ad. Gibson identifies 'Ad with the Edomites and the Hyksos supported by various archaeological proofs. Years later Arabia united again under the Midianites. Some centuries later the Nabataeans unite Arabia. The Qur'an calls them the people of Thamud. In 600 AD the Arabian Peninsula was united under the flag of Islam.But there is more to this book than a study of the four times when the Arabs demonstrated their greatness. This book also examines the geographical references in the Qur'an cross-referencing them with historical locations. The surprise comes when Gibson examines the Holy City of Islam, known as Mecca. Here Gibson finds evidence that the original Holy City was in northern Arabia in the city of Petra. He theorizes that during an Islamic civil war the Ka'ba was destroyed and the Black Rock moved to its present location. Gibson examines archaeological, historical and literary evidence that support this theory. This book contains many references, as well as some useful appendices including a 32 page time line of Islamic history from 550 AD - 1095 AD, and a 20 page annotated selected bibliography of early Islamic sources in chronological order from 724 AD - 1100 AD plus a list of many early Qur'anic manuscripts. Easy to read, fully referenced with many illustrations and photos.