The Quran is viewed to be the scriptural foundation of Islam and is believed by Muslims to have been sent down by God (Arabic: الله, romanized: Allah) and revealed to Muhammad by the angel Jibrael (Gabriel). The Quran has been subject to criticism both in the sense of being the subject of an interdisciplinary field of study where secular, (mostly) Western scholars set aside doctrines of its divinity, perfection, unchangeability, etc. accepted by Muslim Islamic scholars; but also in the sense of being found fault with by those — including Christian missionaries and other skeptics hoping to convert Muslims — who argue it is not divine, not perfect, and/or not particularly morally elevated.

In critical-historical study scholars (such as John Wansbrough, Joseph Schacht, Patricia Crone, Michael Cook) seek to investigate and verify the Quran's origin, text, composition, and history, examining questions, puzzles, difficult text, etc. as they would non-sacred ancient texts. The most common criticisms concern various pre-existing sources that the Quran relies upon, internal consistency, clarity and ethical teachings. According to Toby Lester, many Muslims find not only the religious fault-finding but also Western scholarly investigation of textual evidence "disturbing and offensive".

According to Islamic tradition, which criticism may question or contradict, the Quran followed a passage from heaven down to the angel Gabriel (Jabreel) who revealed it in the seventh century CE over 23 years to a Hejazi Arab trader and shepherd, Muhammad, who became one of the Prophets of Islam. Muhammad shared these revelations – which brought uncompromising monotheism to humanity – with his companions who wrote them down and/or memorized them. From these memories and scraps, a standard edition was carefully compiled and edited under the supervision of Caliph Uthman not long after Muhammad's death. Copies of this codex or "Mus'haf" were sent to the major centers of what was by this time a rapidly expanding empire, and all other incomplete or "imperfect" variants of the Quranic revelation were ordered by Uthman to be destroyed. In the next few centuries, the religion and empire of Islam solidified, and an enormous body of religious literature and laws were developed, including commentaries/exegeses (Tafsir) to explain the Quran.

Thus, according to Islamic teaching, it was ensured that the wording of the Quranic text available today corresponds exactly to the literal, infallible, "perfect, timeless", "absolute" unadulterated word of God revealed to Muhammad. That revelation in turn is identical to an eternal “mother of the book” the archetype/prototype of the Quran. In their religious and theological view, this was not created/written by God, but an attribute of Him, co-eternal and kept with Him in heaven.

For Muslims, the contents of the Quran have been "a source of doctrine, law, poetic and spiritual inspiration, solace, zeal, knowledge, and mystical experience." "Millions and millions" of whom "refer to the Koran daily to explain their actions and to justify their aspirations", and in recent years many consider it the source of scientific knowledge. Revered by pious Muslims as "the holy of holies", whose sound moves some to "tears and ecstasy", it is the physical symbol of the faith, the text often used as a charm on occasions of birth, death, marriage. The traditional Muslim understanding of the Quran is not that it is simply divinely inspired, but the literal word of God; the last and complete message from God, from his final messenger (Muhammad) superseding the Old and New Testament and purified of "accretions of Judaism and Christianity".

Muslims have developed their own Quranic studies or "Quranic sciences" (‘ulum al Qur’an) over the centuries, following the Quranic encouragement "Will they not contemplate the Quran?"(4:82). There are two types of exegesis to explain and interpret the Quran: tafsir (literal interpretation) and ta’wil (allegorical interpretation). Other issues studied are kalimat dakhila (the investigation of the foreign origin of some Quranic terms); naskh (studying contradictory verses to determine which should be abrogated in favor of the other), study of "occasions of revelation" (connecting Quranic verses with "episodes of Muhammad's career based on hadith and biographies of him -- which are known as sira), chronology of revelation, the division of quranic chapters (surahs) into "Meccan surah" (those believed to have been revealed in Mecca before the hijra) and "Medinan surah (revealed afterward in the city of Medina). According to Seyyed Hossein Nasr, these traditional religious sciences

"provide all the answers to questions posed by modern western orientalists about the structure and text of the Koran, except, of course, those questions that issue from the rejection of the Divine Origin of the Koran and its reduction to a work by the prophet. Once the revealed nature of the Koran is rejected, then problems arise. But these are problems of orientalist that arise not from scholarship but from a certain theological and philosophical position that is usually hidden under the guise of rationality and objective scholarship. For Muslims there has never been the need to address these 'problems' ..."

In contrast, many of the original non-Muslim scholars of the Quran worked "in the context of an openly declared hostility" between Christianity and Islam, with an eye to debunking Islam or proselytizing against it. The nineteenth-century orientalist and colonial administrator William Muir, wrote that the Quran was one of "the most stubborn enemies of Civilisation, Liberty, and the Truth which the world has yet known." In the twentieth century, scholars of the early Soviet Union^[who?] working in the context of dialectical materialism and fighting the "opium of the people" argued that Muhammad and the first Caliphs were "mythical figures" and that "the motive force" of early Islam was "the mercantile bourgeoisie of Mecca and Medina" and "slave-owning" Arab society.