The following is the report transmitted in the Sahih Bukhari:
Narrated Anas bin Malik: Hudhaifa bin Al-Yaman came to 'Uthman at the time when the people of Sham and the people ofIraq were waging war to conquer Arminya and Adharbijan. Hudhaifa was afraid of their (the people of Sham and Iraq) differences in the recitation of the Qur'an, so he said to 'Uthmfin, 'O chief of the Believers! Save this nation before they differ about the Book (Qur'an), as Jews and the Christians did before'. So 'Uthman sent a message to Hafsa saying, 'Send us the manuscripts of the Qur'an so that we may compile the Qur'anic materials in perfect copies and return the manuscripts to you'. Hafsa sent it to 'Uthman. 'Uthman then ordered Zaid bin Thabit, 'Abdullah bin Az-Zubair, Sa'id bin Al-'As and 'Abdur Rahman bin Hari-bin Hisham to rewrite the manuscripts in perfect copies. 'Uthman said to the three Quraishi men, 'In case you disagree with Zaid bin Thabit on any point in the Qur'an, then write it in the dialect of Quraish as the Qur'an was revealed in their tongue'. They did so, and when they had written many copies, 'Uthman returned the original manuscripts to Hafsa. 'Uthman sent to every Muslim province one copy of what they had copied, and ordered that all the other Qur'anic materials whether written in fragmentary manuscripts or whole copies, be burnt. Zaid bin Thabit added, 'A verse from Sura al-Ahzab was missed by me when we copied the Qur'an and I used to hear Allah's Apostle reciting it. So we searched for it and found it with Khuzaima bin Thabit Al-Ansari'. (That verse was): 'Among the Believers are men who have been true in their convenant xwith Allah' (33: 23). [Bukhari, VI, No. 510]

The following events led to the preparation of the mushaf of 'Uthman:

Disputes had arisen among the Muslims about the correct manner of reciting the Qur'an.

'Uthman borrowed the suhuf, which were kept with Hafsa.

'Uthman ordered four Companions, among them Zaid bin Thabit, to rewrite the script in perfect copies.

'Uthman sent these copies to the main centres of the Muslims to replace other materials that were in circulation.

Chronology of the Written Text

Around 610

Muhammad's Prophethood commences.

1st revelation in cave onMountHira

Transmitted orally, later in written form.

610-32

Muhammad in Makka and Madina.

Continious revelation on numerous occasions

Transmitted orally after memorisation by many, and writing down of revelation by various companions upon the direct instruction of the Prophet himself.

632

Prophets death.

Last revelation few days before this.

Compelete revelation left behind both in the memories of various companions as well as on various writing materials.

At the death of the Prophet, complete revelation left behind.

632-34

Abu Bakrs caliphate

633

During the battle of Yamama several companions who knew the Quran by heart were killed.

Abu Bakr instructs Zaid b. Thabit to prepare a single copy of the complete revelation.

Zaid b. Thabit brings together all the revelation into the suhuf from both oral as well as written sources demanding two witnesses for each piece. The Suhuf remain with Abu Bakr.

During the 1st/2nd year after the Prophets death the entire revelation was copied onto sheets (suhuf).

634-44

Umar's Caliphate.

The suhuf remain with Umar.

644-56

Uthmans Caliphate.

The suhuf remain with Hafsa bint Umar.

653

Campaign against Armenia and Azerbaidjan.

Serious differences arose among muslims about the correct recitation of the Quran. Uthman instructs Zaid together with three other sahaba to prepare copies from the suhuf kept with Hafsa.

Zaid and three Companions prepare a number of fresh copies from the suhuf. These copies are sent to the various muslim regions to replace other material in circulation. Suhuf returned to Hafsa. ‘Uthman also keeps one copy (mushaf).

Several copies of the entire revelation available through out the muslim lands.

What the Prophet left to the Muslims

The revelation, as left by the Prophet, was available both orally and written on various materials. Its internal order was known to the Muslims and strictly observed by them.
Abu Bakr collected these loose materials and had their contents written on to sheets (suhuf).

The Difference between Abu Bakr's and 'Uthman's Collection

Abu Bakr had made one single copy from the various verbal and written materials. This copy was later kept by 'Umar and then by his daughter Hafsa.

'Uthman had many copies prepared from this copy and sent them to various places in the Muslim world, while the original suhuf were returned to Hafsa and remained with her until her death. Later, Marwan b. Hakam (d. 65/684), according to a report in Ibn Abi Dawud, collected it from her heirs and had it destroyed, presumably fearing it might become the cause for new disputes. 'Uthman also kept one of the copies for himself. This version of the text, also known as 'Mushaf 'Uthman in fact constitutes the ijma'(consensus) of the sahaba, all of whom agreed that it contained what Muhammad had brought as revelation from Allah. [According to Ibn Abi Dawud (117-8) eleven changes wcre madu under al-Hajjaj, among them e.g.5:48 'shari'atan wa minhajan' into 'shir'atan wa minhajan'; 12:45 'ana atikum bi-ta'wilihi' into and unabbi'ukum bi ta'wilihi. These are again according to Ibn Abi Dawud mistakes which were made in the preparation of Uthmans copy (pp. 37-49). The first version of12:45 e.g. was the reading of 'Ubay (ibid. p. 138) and Ibn Masud (ibid. p. 39).]

The wide distribution of this text and its undisputed authority can also be deduced from the reports on the battle of Siffin (A.H. 37) 27 years after the death of the Prophet, and five years after 'Uthman's copies were distributed, Mu'awiya's troops fixed sheets from the Qur'an on their spears to interrupt the battle. [See Suyuti, History of the Caliphs. transl. H. S. Jarrett. BaptistMission Presss Calcutta. 1881, p. 177.] However nobody accused anyone else of using a 'partisan' version of the text, which would have made a splendid accusation against the enemy.