Who wrote the Quran?

The Islamic belief is that the Quran is the literal word o God which was revealed to Mohammed via the angel Gabriel (Jibrail).During the time of Mohammed a few people wrote down what they heard, but the primary means of learning and transmitting the Quran was vocally and to commit it to memory.After the death of Mohammed there were moves to codify the Quran into a book (thus helping in prostelysing).I believe it was under the Caliph Omar that the final draft was made comparing the text with other versions that may have existed.The other versions were burnt,and the Quran as it is now known came into existence. There are of course a few theories put forward by other thinkers that contrast with this view on the codification of the Quran but I am not too well versed in them.

The quraan is the only book that has not been altered (changed) and yes it was sent down to the prophet muhammad s.a.w

Actually the Quran was changed a few times do your history my friend

L8R

It was sent down through the ProphetPBUH. His followers asked if they could write it down so that his teachings would be recorded.