The Qur'an was revealed to Prophet Muhammad (PBUH) over about 23 years through Angel Jibril, first in the Cave of Hira. It has 114 surahs, divided into 30 juz. Makki surahs were revealed in Makkah, Madani in Madinah. It was written down during the Prophet's time, collected into one book under Caliph Abu Bakr and standardised under Caliph Uthman. Tajweed is the science of correct recitation.