By Gerald Butt
Middle East analyst
The history of Saudi Arabia is entwined - as much as its name is - with the fate and fortunes of the House of Saud, which traces its origins back to the 18th century.
Saudi Arabia adheres to the strict Wahhabi interpretation of Islam
By the middle of that century the clan had become members of the Wahhabi sect - in those days a militantly puritanical branch of Sunni Islam that denounced some other Muslim sects as apostates.
Wahhabism was the catalyst for the emergence of the Saud dynasty as a powerful military force in the Arabian peninsula and was the foundation on which the Kingdom of Saudi Arabia was eventually unified and built.
Today, Wahhabism is practised with less rigour than in the 18th and 19th centuries. Nevertheless, in modern-day Saudi Arabia, Wahhabi doctrine ensures that life in the kingdom is far more constrained than in other Arab states.
Not only is alcohol strictly forbidden, but shops are required to close for the five-times-daily prayers, women are not allowed to drive vehicles or play an active part in public life, cinemas are banned and public worship of any religion other than Islam is proscribed.
In the 19th century, as the House of Saud attempted to extend its rule over the Arabian peninsula, it found a rival in the Rashid clan, which enjoyed the support of the Ottoman Empire.
A Rashid victory in the 1890s saw the Sauds, led by Abdul Aziz Al Saud, exiled in Kuwait.
But fortunes were reversed in 1902, when the Sauds hit back, recapturing their ancestral home, Riyadh, and gaining control of most of the eastern Arabian peninsula in the following years.
The collapse of the Ottoman Empire after World War I enabled them to seize the western part of the peninsula, including the sacred Islamic cities of Mecca and Medina.
Ultimate power rests with the Saudi throne - established in 1932 and occupied by Abdul Aziz until his death in 1953 and four of his sons since then.
In 1996, when King Fahd suffered a stroke, day-to-day affairs of state were passed to Crown Prince Abdullah, who has become de facto ruler.
Abdullah succeeded to the throne at the death of Fahd in August 2005.
The decision-making process within the royal family is a discreet affair, with senior princes discussing issues in private with the aim of eventually reaching a consensus. Such disagreements as may exist are never aired in public.
Crown Prince Abdullah is the de facto ruler and a cautious reformer
The informal consultation process appeared to be given a more formal structure with the formation in June 2000 of a family council chaired by Crown Prince Abdullah and comprising 18 princes.
Decisions affecting daily life in Saudi Arabia are taken by the Council of Ministers (cabinet). But here again the royal family is strongly represented, with King Abdullah serving as prime minister and other senior figures in the House of Saud holding the key foreign affairs, defence and interior portfolios.
While other cabinet members would be expected to defer to the wishes of the royal family on major issues of state, they are not without influence in their own sectors.
For example, in 1998 Crown Prince Abdullah and Foreign Minister Prince Saud al-Faisal proposed a scheme for foreign firms to invest in the exploitation of new gas deposits.
But the project was successfully opposed by the state-owned energy company, Saudi Aramco, championed by Oil Minister Ali al-Nuaymi and some members of the royal family.
One of the cabinet's roles is to enact legislation. Draft laws first require the approval of the Majlis al-Shura (Consultative Council).
This body was established, initially with 60 members appointed by the king, in 1992. The membership was increased to 90 appointees in 1997 and to 120 in 2001. The duration of each council is four years.
As well as approving proposed legislation, the Shura Council has the power to summon and question government ministers.
Abdul Aziz 1932-1953
Fahd 1982 to 2005
Abdullah 2005 to present
In March 2004, Second Deputy Prime Minister and Defence Minister Prince Sultan - now crown prince - said there would not be elections for the Shura Council in the foreseeable future, but he did not rule out the possibility at some point in the future.
While the king and senior princes maintain the ancient Arabian tradition of the majlis - a form of open assembly - in their palaces, to give ordinary citizens the right to present petitions or air grievances, popular political participation has always been restricted and parties are banned.
In October 2003, under pressure from home and abroad, the government announced plans to set up municipal elections with half the seats up for election.
The plan was given a cautious welcome by the public, but critics of the regime saw it as merely a token gesture.
Much of the speculation in the Western media about uncertainty surrounding the succession in Saudi Arabia is either exaggerated or wide of the mark.
In the short term, at least, the picture is clear. Crown Prince Abdullah will be the next king of Saudi of Arabia, and the current Defence Minister, Prince Sultan, will succeed him. After that, the succession is less certain.
All the sons of King Abdul Aziz are of a considerable age. Both Crown Prince Abdullah and Prince Sultan are in their 70s. At some point, the issue of handing power to the second generation will have to be faced - although as yet this is not under discussion.
While the kingdom faces some difficult choices in the years ahead, talk of the collapse of the House of Saud is unrealistic, at least in the foreseeable future. For a start, it is a huge structure, with an estimated 7,000 princes, some in very influential positions.
While differences exist over such issues as relations with the West, and political and economic liberalisation, the family is united in its desire to keep control of the kingdom.
Furthermore, it would be wrong to overlook the fact that the family has many loyal supporters within the kingdom.
The aftermath of the 11 September 2001 attacks and the US-led invasion of Iraq changed the political climate in the Gulf region as a whole.
Saudi Arabia, in particular, came in for harsh criticism from the US for allowing a milieu to develop in the kingdom in which the perpetrators of the bombings could have lived unchecked and money could be channelled to militant Islamic groups. American pressure on the Saudi government to crack down on Islamic charities, change the school curriculum and liberalise and democratise political life increased.
Angered by what was perceived as unwarranted interference in domestic matters, the Saudi leadership was reluctant to take action. But a series of suicide bomb attacks inside the kingdom appeared to convince the government that action should be taken on two fronts, with a crackdown on Islamist militants and the first tentative introduction of reforms.
Khobar siege, May 2004: Militants have repeatedly targeted foreigners
The initiative for the kingdom's nascent reform process has come from Crown Prince Abdullah. He has chaired a series of national dialogue meetings, attended by 60 men and women - clergy, academics and leading opinion-formers in society.
The crown prince has stressed in public - for the benefit of opponents inside the royal family as much as those outside - that the kingdom has no choice but to proceed with the dialogue and introduce changes in its political and social life.
Change is likely to be slow. Compared with all other Arab states, Saudi Arabia is inherently conservative. Crown Prince Abdullah knows that he will be unable to introduce overnight reforms to the political system, school curricula or other sensitive areas. Instead, he is using these preliminary stages of the debate to test the water and see how far he can push things.
BBC Monitoring, based in Caversham in southern England, selects and translates information from radio, television, press, news agencies and the Internet from 150 countries in more than 70 languages.