Muslims believe that the Qur'an was revealed to the Prophet Muhammad by the Angel Gabriel on numerous occasions between the years 610 and Muhammad's death in 632. In addition to memorizing his revelations, his followers are said to have written them down on parchments, stones, and other media, so that the entire Qur'an was written down during the lifetime of Prophet Muhammad.

Muslims believe that the Qur'an available today is the same as that revealed to Prophet Muhammad and by him to his followers, who memorized his words. Scholars accept that the version of the Qur'an used today was first compiled in writing by the third Caliph, Uthman ibn Affan, sometime between 650 and 656. He sent copies of his version to the various provinces of the new Muslim empire, and directed that all variant copies be destroyed. However, some skeptics doubt the recorded oral traditions (hadith) on which the account is based and will say only that the Qur'an must have been compiled before 750.

There are also numerous traditions, and many conflicting academic theories, as to the provenance of the verses later assembled into the Qur'an. Most Muslims accept the account recorded in several hadith, which state that Abu Bakr, the first caliph, ordered Zayd ibn Thabit to collect and record all the authentic verses of the Qur'an, as preserved in written form or oral tradition. Zayd's written collection, privately treasured by Muhammad's widow Hafsa bint Umar, was used by Uthman and is the basis of today's Qur'an.

Uthman's version organized the revelations, or suras, roughly in order of length, with the longest suras at the start of the Qur'an and the shortest ones at the end. More conservative views state that the order of most suras was divinely set. Later scholars have struggled to put the suras in chronological order, and among Muslim commentators at least there is a rough consensus as to which suras were revealed in Mecca and which at Medina. Some suras (eg surat Iqra) were revealed in parts at separate times.

Because the Qur'an was first written (date uncertain) in the Hijazi, Mashq, Ma'il, and Kufic scripts, which write consonants only and do not supply the vowels, and because there were differing oral traditions of recitation, as non-native Arabic speakers converted to Islam, there was some disagreement as to the exact reading of many verses. Eventually, scripts were developed that used diacritical markings (known as points) to indicate vowels. For hundreds of years after Uthman's recension, Muslim scholars argued as to the correct pointing and reading of Uthman's unpointed official text, (the rasm). Eventually, most commentators accepted seven different readings (qira'at) of the Qur'an as canonical.

The form of the Qur'an most used today is the Al-Azhar text of 1923, prepared by a committee at Cairo university of Al-Azhar.

The Qur'an early became a focus of Muslim devotion and eventually a subject of theological controversy. In the 8th century, the Mu'tazilis claimed that the Qur'an was created in time and was not eternal. Their opponents, of various schools, claimed that the Qur'an was eternal and perfect, existing in heaven before it was revealed to Muhammad. The Ashari theology (which ultimately became predominant) held that the Qur'an was uncreated. However, modern liberal movements within Islam are apt to take something approaching the Mu'tazili position.

Most Muslims regard paper copies of the Qur'an with extreme veneration, wrapping them in a clean cloth, keeping them on a high shelf, and washing as for prayers before reading the Qur'an. Old Qur'ans are not destroyed as wastepaper, but burned or deposited in Qur'an graveyards.

Almost every Muslim has memorized some portion of Qur'an in the original language. Those who have memorized the entire Qur'an are known as hafiz. This is not a rare achievement; it is believed that there are millions of hafiz alive today.

Notable messengers include Adam, Noah, Abraham, Moses (Musa), Jesus (Isa), and Muhammad, all belonging to a succession of men guided by God. Islam demands that a believer accept most of the Judeo-Christian prophets, making no distinction between them. In the Qur'an, 25 specific prophets are mentioned.

Mainstream Muslims regard Muhammad as the 'Last Messenger' or the 'Seal of the Prophets' based on the canon. However, there have been a number of sects whose leaders have proclaimed themselves the successors of Muhammad, changing and extending Islam, or, whose devotees have made such claims for their leaders. However, most Muslims remain unaffected by those claims and simply regard those said groups to be deviant from Islam.

Islamic law covers all aspects of life, from the broad topics of governance and foreign relations all the way down to issues of daily living. Islamic law at the level of governance and social justice only applies where the government is Islamic.

According to Islam, the Sharia is divinely revealed. It is understood as protecting five things: faith, life, knowledge, lineage, and wealth. However, it is by no means a rigid system of laws. There are different schools of thoughts and movements within Islam that allow for flexibility. Moreover, Islam is a diverse religion as many cultures have embraced it.

In orthodox Islamic theology, conversion from Islam to another religion is forbidden and punishable by death. Apostasy is public disloyalty towards Islam by any one who had previously professed the Islamic faith. Blasphemy is showing disrespect or speaking ill of any of the essential principles of Islam. There is no sharp distinction made between these concepts, as many believers feel that there can be no blasphemy without apostasy.

In the period of Islamic empire, apostasy was considered treason, and was accordingly treated as a capital offense; death penalties were carried out under the authority of the Caliph. Today apostasy is punishable by death in the countries of Saudi Arabia, Qatar, Yemen, Iran, Sudan, Pakistan, and Mauritania. Blasphemy is also an offence in many of these countries.

In most of these countries, such laws are invoked only sporadically and selectively; convictions tend to be reversed at a higher level, or if not reversed, those convicted may be allowed to leave the country. Some Islamic countries, notably, Saudi, Iran under the Islamic Republic, Afghanistan under the Taliban, and Sudan, have been more willing to enforce laws and punishments against apostasy and blasphemy. In each of these countries Islamist regimes are estimated to have executed, flogged, and imprisoned hundreds or thousands of people believed to be apostates or blasphemers.

Other punishments prescribed by sharia (depending on interpretation) may include the annulment of marriage with a Muslim spouse, the removal of children, the loss of property and inheritance rights, or other sanctions.

Here as elsewhere in Islam, scholars disagree on specific applications of core principles, with some prominently advocating a punitive approach to "exclusionary" issues and others tending to de-emphasize such questions.

The Sunni sect of Islam is the largest of the sects (some 80-85% of all Muslims are Sunni). Sunnis recognize four legal traditions (madhhabs): Maliki, Shafi'i, Hanafi, and Hanbali. All four accept the validity of the others and Muslims choose any one that he/she thinks is agreeable to his/her ideas. There are also several orthodox theological or philosophical traditions (kalam).

Shi'a Muslims differ from the Sunni in rejecting the authority of the first three caliphs. They honor different traditions (hadith) and have their own legal traditions. The Shi'a consist of one major school of thought known as the Ithna Ashariyya or the "Twelvers", and a few minor schools of thought, as the "Seveners" or the "Fivers" referring to the number of infallible leaders they recognise after the death of Muhammad. The term Shi'a is usually taken to be synonymous with the Ithna Ashariyya/Twelvers. Most Shi'a live in Iran, Iraq, and Lebanon.

Sunni and Shi'a have often clashed. Some Sunni believe that Shi'a are heretics while other Sunni recognize Shi'a as fellow Muslims. According to Shaikh Mahmood Shaltoot, head of the al-Azhar University in the middle part of the 20th Century, "the Ja'fari school of thought, which is also known as "al-Shi'a al- Imamiyyah al-Ithna Ashariyyah" (i.e., The Twelver Imami Shi'ites) is a school of thought that is religiously correct to follow in worship as are other Sunni schools of thought". Al-Azhar later distanced itself from this position.

Another sect which dates back to the early days of Islam is that of the Kharijites. The only surviving branch of the Kharijites are the Ibadhi Muslims. Most Ibadhi Muslims live in Oman.

Wahhabis, as they are known by non-Wahhabis, are a more recent group. They prefer to be called the Ikhwan, or Brethren, or sometimes Salafis. Wahhabism is a movement founded by Muhammad ibn Abd al Wahhab in the 18th century in what is present-day Saudi Arabia. They classify themselves as Sunni and some claim to follow the Hanbali legal tradition. The major trend, however is the abolition of these 'schools of thoughts' (legal traditions), and the following of a more literalist interperation. Some even regard other Sunni as heretics. They are recognized as the official religion of Saudi Arabia and have had a great deal of influence on the Islamic world due to Saudi control of Mecca and Medina, the Islamic holy places, and due to Saudi funding for mosques and schools in other countries.

Another trend in modern Islam is sometimes called progressive, liberal or secular Islam. Followers may be called Ijtihadists. They may be either Sunni or Shi'ite, and generally favour the development of personal interpretations of Qur'an and Hadith. See: Liberal Islam

One very small Muslim group, based primarily in the United States, follows the teachings of Rashad Khalifa and calls itself the "Submitters". They reject hadith and fiqh, and say that they follow the Qur'an alone. There is also an even smaller group of Qur'an-alone Muslims who claim to represent the authentic teachings of Rashad Khalifa and seem to have split from the Submitters. Most Muslims of both the Sunni and the Shia sects consider this group to be heretical.

Sufism is a spiritual practice followed by both Sunni and Shi'a. Sufis generally feel that following Islamic law is only the first step on the path to perfect submission; they focus on the internal aspects of Islam, such as perfecting one's faith and fighting one's own ego.

Most Sufi orders, or tariqa, can be classified as either Sunni or Shi'a. There are also some very large groups or sects of Sufism that are not easily categorised as either Sunni or Shi'a, such as the Bektashi. Sufis are found throughout the Islamic world, from Senegal to Indonesia.

* The Zikris

* The Qadianis (or Ahmadiyya)

The following consider themselves Muslims but acceptance by the larger Muslim community varies:

* The Nation of Islam (African-American Cult)

* The Druze

* The Alawites (Alnusairiya)

The following religions are said by some to have evolved or borrowed from Islam, in almost all cases influenced by traditional beliefs in the regions where they emerged, but consider themselves independent religions with distinct laws and institutions:

* Babism

* Bahá'í Faith

* Yazidi

The claim of the adherents of the Bahá'í Faith that it represents an independent religion was upheld by the Muslim ecclesiastical courts in Egypt during the 1920's. As of January 1926, their final ruling on the matter of the origins of the Bahá'í Faith and its relationship to Islam was that the Bahá'í Faith was neither a sect of Islam, nor a religion based on Islam, but a clearly-defined, independently-founded faith. This seen as a considerate act on part of the ecclesiastical court and in favor of followers of Bahá'í Faith since the majority of Muslims would regard a religion based on Islam as a heresy.

Some see Sikhism as a syncretic mix of Hinduism and Islam. However, its history lies in the social strife between local Hindu and Muslim communities, during which Sikhs were seen as the "sword arm" of Hinduism. The philosophical basis of the Sikhs is deeply-rooted in Hindu metaphysics and certain philosophical practices. Sikhism also rejects image-worship and believes in one God, just like the Bhakti reform movement in Hinduism and also like Islam does.

The following religions might have been said to have evolved from Islam, but are not considered part of Islam, and no longer exist:

* The religion of the medieval Berghouata

* The religion of Ha-Mim

The classical Islamic solution was a limited tolerance - Jews and Christians were to be allowed to privately practice their faith and follow their own family law. They were called Dhimmis, and they had fewer legal rights and obligations than Muslims.

The classic Islamic state was often more tolerant than many other states of the time, which insisted on complete comformity to a state religion. The record of contemporary Muslim-majority states is mixed. Some are generally regarded as tolerant, while others have been accused of intolerance and human rights violations. See the main article, Islam and other religions, for further discussion.

Nonetheless, the later empires of the Abbasid caliphs and the Seljuk Turk were among the largest and most powerful in the world. After the disastrous defeat of the Byzantines at the Battle of Manzikert in 1071, Christian Europe launched a series of Crusades and for a time captured Jerusalem. Saladin however restored unity and defeated the Shiite Fatimids.

From the 14th to the 17th centuries one of the most important Muslim territories was the Mali Empire, whose capital was Timbuktu.

In the 18th century there were three great Muslim empires: the Ottoman in Turkey, the Middle East, and the Mediterranean; the Safavid in Iran; and the Mogul in India. By the 19th century, these realms had fallen under the sway of European political and economic power. Following WWI, the remnants of the Ottoman empire were parceled out as European protectorates or spheres of influence. Islam and Islamic political power have revived in the 20th century. However, the relationship between the West and the Islamic world remains uneasy.

Early shariah had a much more flexible character than is currently associated with Islamic jurisprudence, and many modern Muslim scholars believe that it should be renewed, and the classical jurists should lose their special status. This would require formulating a new fiqh suitable for the modern world, e.g. as proposed by advocates of the Islamization of knowledge, and would deal with the modern context. One vehicle proposed for such a change has been the revival of the principle of ijtihad, or independent reasoning by a qualified Islamic scholar, which has lain dormant for centuries.

This movement does not aim to challenge the fundamentals of Islam; rather, it seeks to clear away misinterpretations and to free the way for the renewal of the previous status of the Islamic world as a center of modern thought and freedom. See Modern Islamic philosophy for more on this subject.

The claim that only "liberalization" of the Islamic Shariah law can lead to distinguishing between tradition and true Islam is countered by many Muslims with the argument that any meaningful "fundamentalism" will, by definition, reject non-Islamic cultural inventions - by, for instance, acknowledging and implementing Muhammad's insistence that women have God-given rights that no human being may legally infringe upon. Proponents of modern Islamic philosophy sometimes respond to this by arguing that, as a practical matter, "fundamentalism" in popular discourse about Islam may actually refer, not to core precepts of the faith, but to various systems of cultural traditionalism.

Commonly cited estimates of the Muslim population today range between 900 million and 1.4 billion people (cf. Adherents.com); estimates of Islam by country based on US State Department figures yield a total of 1.48 billion, while the Muslim delegation at the United Nations quoted 1.2 billion as the global Muslim population in Sept 2005.

Only 18% of Muslims live in the Arab world; 20% are found in Sub-Saharan Africa, about 30% in the Indian sub-continental region of Pakistan, India and Bangladesh, and the world's largest single Muslim community (within the bounds of one nation) is in Indonesia. There are also significant Muslim populations in China, Europe, Central Asia, and Russia.

France has the highest Muslim population of any nation in Europe, with up to 6 million Muslims (10% of the population[2]). Albania is said to have the highest proportion of Muslims as part of its population in Europe (70%), although this figure is only a (highly contested) estimate (see Islam in Albania). The number of Muslims in North America is variously estimated as anywhere from 1.8 to 7 million.

The reference to the Qur'an is verifiable; it is not clear if the other traditions are reliable or mere folklore. However, the association between Islam and the color green is firmly established now, whatever its origins may have been.

* The color green is absent from medieval European coats of arms as during the Crusades, green was the color used by their Islamic opponents.

* In the palace of Topkapi, in Istanbul, there is a room with relics of Muhammad. One of the relics, kept locked in a chest, is said to have been Muhammad's banner, under which he went to war. Some say that this banner is green with golden embroidery, others say that it is black and others think there is no banner in the chest at all.

In early accounts of Muslim warfare, there are references to flags or battle standards of various colors: black, white, red, and greenish-black. Later Islamic dynasties adopted flags of different colors:

* The Ummayads fought under white banners

* The Abbasids chose black

* The Fatimids used green

* Various countries on the Persian Gulf have chosen red flags

These four colors, white, black, green and red, dominate the flags of Arab states.

The crescent and star are often said to be Islamic symbols, but flag historians citations state that they were the insignia of the Ottoman empire, not of Islam as a whole.

Notes
1. Shi'a muslims do not believe in absolute predestination (Qadar), since they consider it incompatible with Divine Justice. Neither do they believe in absolute free will since that contradicts God's Omniscience and Omnipotence. Rather they believe in "a way between the two ways" (amr bayn al‑'amrayn) believing in free will, but within the boundaries set for it by God and exercised with His permission.
2. The Egyptian Islamic Jihad group claims, as did a few long-extinct early medieval Kharijite sects, that Jihad is the "sixth pillar of Islam." Some Ismaili groups consider "Allegiance to the Imam" to be the so-called sixth pillar of Islam. For more information, see the article entitled Sixth pillar of Islam.