Muslims believe the Quran was verbally revealed by God to Muhammad through the angel Gabriel (Jibril), gradually over a period of approximately 23 years, beginning on 22 December 609 CE, when Muhammad was 40, and concluding in 632, the year of his death. Muslims regard the Quran as the most important miracle of Muhammad, a proof of his prophethood, and the culmination of a series of divine messages that started with the messages revealed to Adam and ended with Muhammad. The word "Quran" occurs some 70 times in the text of the Quran, although different names and words are also said to be references to the Quran. 

According to the traditional narrative, several companions of Muhammad served as scribes and were responsible for writing down the revelations. Shortly after Muhammad's death, the Quran was compiled by his companions who wrote down and memorized parts of it. These codices had differences that motivated the Caliph Uthman to establish a standard version now known as Uthman's codex, which is generally considered the archetype of the Quran known today. There are, however, variant readings, with mostly minor differences in meaning.
What is the book regarded as?
 standard version now known as Uthman's codex