From Wikipedia

Decoding The Past: Secrets Of The Koran

Part One

The Qur’an , literally “the recitation”; also sometimes transliterated as Quran, Qur’ān, Koran, Alcoran or Al-Qur’ān) is the central religious text of Islam. Muslims believe the Qur’an to be the book of divine guidance and direction for mankind, and consider the original Arabic text to be the final revelation of God.

Islam holds that the Qur’an was revealed to Muhammad by the angel Jibrīl (Gabriel) over a period of approximately twenty-three years, beginning in 610 CE, when he was forty, and concluding in 632 CE, the year of his death. Followers of Islam further believe that the Qur’an was written down by Muhammad's companions while he was alive, although the primary method of transmission was oral. Muslim tradition agrees that it was fixed in writing shortly after Muhammad's death by order of the caliphs Abu Bakr and Umar, and that their orders began a process of formalization of the orally transmitted text that was completed under their successor Uthman with the standard edition known as the "Uthmanic recension". The present form of the Qur’an is accepted by most scholars as the original version authored or dictated by Muhammad.