The Kingdom of Saudi Arabia is one of the main players in the Arab world.
Its stature is built on its prestige as the custodian of the birthplace of Islam, and its status as an one of the world's largest oil producers.
Its importance as an oil exporter has made economic interdependence with the West - where the main consumer demand is found - a necessity.
This, in turn, has led to strong political and military relationships that at times have been a source of awkwardness for both sides.
It stands out for its espousal of a puritan version of Sunni Islam, including harsh punishments such as public beheadings, and its restrictions on the rights of women.
In recent years, there has been a growing regional rivalry with Iran.
King Salman bin Abdulaziz al-Saud
The Al Saud dynasty holds a monopoly of political power. King Salman bin Abdulaziz al-Saud ascended the throne in January 2015 following the death of his half-brother Abdullah.
He has been part of the ruling group of princes for decades, and has continued the main thrusts of Saudi strategic policy - maintaining the US alliance and working towards energy market stability.
Crown prince: Mohammed bin Salman
King Salman made his son Mohammed bin Salman heir-apparent in June 2017, and the latter now controls all the major levers of power.
There are no democratic institutions in Saudi Arabia, with the systematic repression of human rights activists, women's rights activists, journalists and political dissidents.
The crown prince was personally linked to the assassination of Saudi Arabian Washington Post columnist Jamal Khashoggi, who had criticised the Saudi government. He has denied involvement in the killing.
Saudi investors are major players in the pan-Arab TV industry, but the country has one of the region's most tightly-controlled media environments.
The government openly acknowledges that widespread internet filtering takes place. It targets "pornographic", Islam-related, human rights and political sites.
Saudi Arabia has the highest per-capita YouTube use of any country in the world. It is reportedly home to more than 40% of all active Twitter users in the Arab region.
Some key events in Saudi history:
1727 - Muhammad bin Saud, founder of the Saudi royal dynasty, joins forces with religious leader Muhammad ibn Abd al-Wahhab, founder of the Wahhabi movement, a strict puritanical form of Sunni Islam.
1932 - The Kingdom of Hejaz and Sultanate of Nejd - the areas controlled by Abdulaziz bin Abdul Rahman Al Saud, known in the West as Ibn Saud - are unified under the name Kingdom of Saudi Arabia.
1938 - Oil is discovered and production begins under the US-controlled Arabian American Oil Company (Aramco).
1960 - Saudi Arabia is a founding member of the Opec Organisation of Petroleum Exporting Countries.
1972 - Saudi Arabia gains control of 20% of Aramco, lessening US control over Saudi oil.
1973 - Saudi Arabia leads an oil boycott against the Western countries that supported Israel in the October Yom Kippur War with Egypt and Syria. Oil prices quadruple.
1979 - Extremists seize the Grand Mosque of Mecca; the government regains control after 10 days and those captured are executed.
1980 - Saudi Arabia takes full control of Aramco from the US.
1981 May - Saudi Arabia is a founder member of the GCC (Gulf Cooperation Council).
1990 - Saudi Arabia condemns Iraq's invasion of Kuwait and asks the US to intervene.
1991 - Saudi Arabia is involved in both air attacks on Iraq and the ground forces that liberate Kuwait.
2001 11 September - 15 of the 19 hijackers involved in attacks on New York and Washington are Saudi nationals.
2005 - World Trade Organization gives the green light to Saudi Arabia's membership following 12 years of talks.
2010 - US officials confirm plan to sell $60bn worth of arms to Saudi Arabia - the biggest single arms deal in US history.
2012 - Saudi women athletes allowed to compete in the Olympics for the first time.
2014 - Saudi Arabia and four other Arab states join with US in air strikes against Islamic State militant strongholds in Syria.
2015 - Saudi Arabia launches campaign of air strikes against Houthi rebels in Yemen.
2017 - Ban on women driving formally lifted.
2018 - Public cinema returns, almost 40 years after it was banned as un-Islamic.
2018 - The killing of emigre reporter Jamal Khashoggi in the Saudi consulate in Istanbul causes an international outcry.