The companions of Allah's final Messenger, Muhammad (peace be upon him) writ the Qur'an within his lifetime. He would tell them what to write, and they would write it. Other companions who were able to read/write also were with the one who writ, so that if any mistakes were made - they could correct him. Then they would recite what was written to ensure that it was written correctly without error.
The Qur’an is a book of guidance and direction for the whole of mankind. It is the Words of Allah, which were conveyed in Arabic to the Prophet Muhammad (peace be upon him.) The Qur’an, sometimes spelt Koran was relayed to the Prophet’s companions, which they memorised verbatim. It was completely written down in the lifetime of the Prophet (peace be upon him.) So unlike other scriptures, the Qur’an was always known to be God’s Word (it wasn’t something decreed by a religious council many years after being written) and, due to widespread memorisation, it was perfectly preserved. The Qur’an is a universal scripture, and it is addressed to all of mankind, and not to a particular tribe or “chosen people”. The message it brings is the same message of all the prophets – submit to Almighty God and worship Him Alone.
As regard your question, we’d like to cite for you the following:
“The Holy Qur'an was presented to the people of Arabia by the Holy Prophet Muhammad, peace and blessings be upon him. It was presented in parts over a period of 23 years of his prophetic life. The book presents itself as the word of Allah and the Holy Prophet also presented it as such.
The Muslims believe that the Holy Qur'an, being the revealed word of Allah, is the cornerstone of their faith. They get their philosophy, beliefs and laws from this book it is the basic source of the Islamic faith. It is the Word of Allah revealed to His Messenger, Muhammad, peace be upon him, who read it out before the world loud and clear. Not only did he recite it to the people of Arabia, he also made elaborate arrangements to ensure that its contents be preserved and his Companions should learn it by heart and should also write it down. The Holy Prophet's stress on the supremacy of the Book of Allah, over all other sources of knowledge, was unequivocal and categorical.
The Holy Qur'an has reached us through Tawatur:
The Holy Qur'an has reached us through the process of
Tawatur (historical continuity and perpetuation achieved through transfer from generation-to-generation) When we say that the Qur'an has reached us through
Tawatur, we imply that so many people in every generation conveyed it to the next and so on that there can be no doubt about its authenticity. It was not transmitted by a few persons in one generation to a few persons in the next. It was handed over by the entire generation to the next generation. The Generation of the Companions witnessed the revelation and compilation of the Holy Qur'an during the life of the Holy Prophet, peace and blessings be upon him, and then handed it over to the next generation and so on.
Its certainty has far exceeded the need for any debate. In the presence of established history, we would not accept any individual reports and rumors to the contrary. For instances a report in one of the history books that claims that Akbar the Great never ruled in India, would not be considered by us. The fact that Akbar the Great ruled over India for half a century is so established, that any odd report to the contrary would be simply ignored. So is the case of the Holy Qur'an. Since it has achieved the status of
Tawatur, no odd report would affect its credibility.
When generations and generations of people without interruption hold the Qur'an as the one and only version of the divine guidance received from the Holy Prophet, such reports would not infringe upon its authenticity. The evidence for the Qur'an is so overwhelming, involving millions of people, that it would simply override any odd reports that may be found anywhere.”
Excerpted, with slight modifications, from
http://www.sunnahonline.com/ilm/quran/0005.htm
In the light of the above, dear brother, it’s clear that all what non-Muslims say or fabricate against the Glorious Qur’an is totally groundless, for the authenticity of the Qur’an is not only upheld by Muslims but confirmed by non-Muslims as well, as will be clarified in the following:
“Attesting to the Qur'an’s authenticity, in his best-seller book
The Bible, The Qur’an and Science the French researcher, historian, scientist Dr. Maurice Bucaille writes:
"Thanks to its undisputed authenticity, the text of the Qur’an holds a UNIQUE Place among the books of Revelation, shared neither by the Old nor the New Testament. In the first two sections of this work (meaning his book), a review was made of the alterations undergone by the Old Testament and the Gospels before they were handed down to us in the form we know today. The same is not true for the Qur’an for the simple reason it was written down at the time of the Prophet; we shall see how it came to be written, i.e. the process involved . . .. As the Revelation progressed, the Prophet and the believers following him recited the text by heart, and it was written down by the scribes in his following. It therefore starts off with two elements of authenticity that the Gospels do not possess."
Professor Hitte also writes: "Biblical text has been subjected to editorial and amendatory treatment, but not the Qur’anic ... In its phonetic and graphic reproduction, as well as in its linguistic form, the Qur’anic text is identical with its celestial original. "
The Qur’an is unique in consistency, harmony, intelligence and rationality:
The Qur’an is the book without inconsistencies; one part of its text, (or doctrine) does not clash with the other. In fact, it sets the absence of contradiction, irrationality, and incoherence, as one of the criteria for checking the authenticity of any divine revelation. It states
"Do they not ponder the Qur’an (with care)? Had this book been from anybody but Allah, you would have found much inconsistencies.” (Surat An-Nisa:82).
Because contradictions and inconsistencies call for the negation of one part, which is in conflict with the other and this automatically invalidates portions of the book. In turn that makes it difficult for a man to remain true to any one value, thereby creating mental conflict, emotional and spiritual instability. "Skip some, follow some," “pick and choose" and "no absolutes" become the pattern. And these exercise an extremely damaging influence upon a truth-conscious, rational man with regard to belief in Allah and with regard to the credibility of the book itself. And it leads to dilemmas where sincere minds become "disjointed" and "disenchanted," eventually steering them away from the book or turn them into hypocrites.
Dr. Maurice Bucaille, who had absolutely no reason to favor one book, especially that of Islam, over the others (if anything, as human nature is, he would only favor the books of his own religion, but not the Qur’an) attests to the Qura’nic claim in his book. "The Quran ... is not only free from contradictions in its narrations, the sign of various human manipulations to be found in the Gospels, but provides a quality of its own for those who examine it objectively and in the light of science i.e. its complete agreement with modern scientific data.”
The Book may be great but what is its impact on the people, you might ask. If no impact it has any significance. How true! The Qur’an is unique in terms of its Blitzing Impact, also.
There have been many other religious books and revelations before the Qur’an. But of these, only the Holy Qur’an had the most electrifying impact upon the people. Its lightning-like rapidity, in a short few decades, reached the hearts and minds of the masses of several continents, transforming the lives of idolaters, alcoholics, exploiters, abusers, perverts, into men and women of pristine monotheism, of highest virtue and piety. Call it what you may - the most sensational spiritual revolution, or the spiritual blitzkrieg, the revolution of which the mankind had never witnessed before. To this very day, no other religion comes even close to matching Qur’an's record of the spectacular impact on lives of masses.”
Excerpted, with slight modifications, from
http://www.iica.org/invitation/the_glor.html