Most of us Westerners know very little about the Middle East and the people that live there. This lack of knowledge hurts our ability to understand, and engage in intelligent discussion about events that happen both there and elsewhere in the Muslim world.
For example, the difference between Sunni and Shia Muslims, and most think the words "Arab" and "Muslim" are the same thing. They aren't. So here's a very brief primer aimed at raising the level of knowledge about the region to an absolute minimum.
1: Arabs are part of an ethnic group, not a religion. Arabs were around long before Islam, and there have been (and still are) Arab Christians and Arab Jews. In general, you're an Arab if you are of Arab descent (blood) or speak the main Arab language (Arabic).
2: Not all Arabs are Muslim. There are significant populations of Arab Christians throughout the world, including in Lebanon, Syria, Jordan, Northern Africa and Palestine/Israel.
3: Islam is a religion. A Muslim (roughly pronounced MOOSE-lim) is someone who follows the religion. So you wouldn't say someone follows Muslim or is an Islam, just as you wouldn't say someone follows Christian or is a Christianity.
4: Shia Muslims are similar to Roman Catholics in Christianity. They have a strong clerical presence via Imams and promote the idea of going through them to practice the religion correctly. Sunni Muslims are more like Protestant Christians. They don't really focus on Imams and believe in maintaining a more direct line to God than the Shia.
5: People from Iran are also known as Persians, and they are not Arabs.
6: Arabs are Semites. We've all heard the term anti-Semitism being used — often to describe Arabs. While anti-semitism does specifically indicate hatred for Jews, the word "Semite" comes from the Bible and referred originally to anyone who spoke one of the Semitic Languages.
7: According to the Bible, Jews and Arabs are related [Genesis 25]. Jews descended from Abraham's son Isaac, and Arabs descended from Abraham's son Ishmael. So not only are both groups Semitic, but they're also family.
8: Sunni Muslims make up most of the Muslim world (roughly 90%).
9: The country with the world's largest Muslim population is Indonesia.
10: The rift between the Shia and Sunni started right after Muhammad's death and originally reduced to a power struggle regarding who was going to become the authoritative group for continuing the faith.
The Shia believed Muhammad's second cousin Ali should have taken over (the family/cleric model). The Sunni believed that the best person for the job should be chosen by the followers (the merit model) and that's how the first Caliph, Abu Bakr, was appointed.
Although the conflict began as a political struggle it is now mostly considered a religious and class conflict, with political conflict emanating from those rifts.
Sunni and Shia | Arab and Non-Arab
Here's how the various Middle Eastern countries break down in terms of Sunni vs. Shia and whether or not they are predominantly Arab. Keep in mind that these are generalizations; significant diversity exists in many of the countries listed.
Iraq - Mostly Shia (roughly 60%), but under Saddam the Shia were oppressed and the Sunni were in power despite being only 20% of the population. Arab.
Iran - Shia and NOT Arab.
Palestine - Sunni and Arab.
Egypt - Sunni and Arab.
Saudi Arabia - Sunni and Arab.
Syria - Sunni and Arab.
Jordan - Sunni and Arab.
Gulf States - Sunni and Arab.
I hope this list will help to promote a better understanding of what an Arab and Muslim are and provide a greater perspective when viewing news about the Middle East and the wider Muslim world.