It was during the reign of the first caliph, Abu Bakr, that the Qur'an was first compiled as a complete book bound between its covers.
Although the Qur'an was transcribed on leather sheets and other such materials during the life time of Muhammed (S.A.W) himself, they were never the main source for the study of the Qur'an on which the society depended. It was, in fact, the services of those who had learnt the whole Qur'an by heart on which the people counted. After the death of the Prophet, Abu Bakr (r) assumed the leadership of the Islamic state. When Musaylama the false prophet arraigned his powerful tribe - the Banu Haneef - against Abu Bakr (r), fighting broke out. The Muslims emerged victorious in the war. The greatest loss suffered by the Muslims, however, was the martyrdom of seventy of those who had memorized the whole of the Qur'an.
It was this incident which led Umar (r), one of the most important figures among the companions of the Prophet, to contemplate over the protection of the Qur'an. He discussed the measures that were to be taken for the purpose with the Caliph Abu Bakr (r). The Caliph was, thereby, convinced of the necessity of the compilation of the Qur'an as a complete book. He, thus, entrusted the task of compiling the Qur'an into a single book to Zaid bin Thabit, the official scribe of the Prophet and the most important of those who wrote down the Qur'an. Zaid bin Thabit himself had memorized the whole Qur'an. However, in the compilation of the Qur'an it was not just his memory on which he depended. He examined the Qur'anic scrolls which were in the possession of several persons. Further, he accepted the versions of only those who could produce at least two eye witnesses who had seen the scrolls being written in the presence of the Prophet himself. Whenever those with the scrolls came to him, he compared their version with his own as also with his memory - in such strict fashion did he continue with his task. Thus, Zaid bin Thabit compiled the whole Qur'an into a single book bound together by its covers. Such a compilation, bound as it was between two covers, came to be known as Mushaf. In short, therefore, it was Zaid bin Thabit, who, during the reign of Abu Bakr (r), compiled the first Mushaf which included, between its covers, the entire Qur'an.