The Holy Quran
The teachings of Muhammad were not written down in a single book during his lifetime. Instead, they were recorded on whatever happened to be available to the people at the time, including bones, palm tree husks, and scrolls. Islamic legend states that these revelations were given to Muhammad by the angle Gabriel over a period of 22 years.
After his death, a new leader by the name of Abu Bakr rose to power. Abu Bakr ordered that all the teachings of Muhammad should be recorded into a single work, or book. He had the people throughout the land search for all the teachings of Muhammad. After two decades, these works were gathered into a single book which became known as the Holy Quran.
The Holy Quran established the religious beliefs and practices of the Islamic people. It also established appropriate practices of both leaders and subjects within government, within their personal lives, and within their livelihoods.
This book was instrumental in insuring that the beliefs of the Muslims remained constant throughout the many centuries since the religion's foundation.