Fahd ibn Abdul-Aziz, the new monarch of Saudi Arabia, has been the kingdom's most influential leader and has run its day-to-day business as crown prince for the past seven years.

As a result, his ascension to the throne is not expected to cause any dramatic change in the cautiously pro-Western policies of the world's largest oil exporter.

Fahd, born in 1922, has long been identified by U.S. policy makers as the key to stability and stronger American ties to Saudi Arabia. He has presided over the Saudi policy of pumping extra oil in times of shortage to curb price increases and reportedly feels a strong sense of responsibility toward the rest of the world in setting petroleum policy. According to highly reliable sources in Riyadh, he initially opposed the 1973-74 Arab oil embargo.

As crown prince, Fahd also has served as the Saudis' chief spokesman on policy toward Israel, in which he has appeared to shift position in the past two years.

In August 1980, Fahd urged a jihad, or Moslem holy war, against the Jewish state. Last year, however, he outlined an eight-point plan for Middle East peace offering implicit recognition of Israel's right to exist in exchange for Israeli withdrawal from all occupied territories and creation of a Palestinian state with its capital in East Jerusalem.

Both Israel and Arab hard-liners rejected the Fahd plan, as it is called, but it remains the best-known alternative to the Camp David peace process backed by the United States. While Fahd is more open to Israel than Arab radicals, he takes seriously the Saudis' traditional task of guarding Islamic shrines such as those in East Jerusalem and has always insisted on Israeli withdrawal from there.

Fahd was groomed for leadership by former King Faisal and became crown prince when Faisal was assassinated in March 1975. More dynamic and experienced than the ailing King Khalid, who succeeded Faisal, Fahd quickly became the principal Saudi decision-maker.

Like both Khalid and Faisal, Fahd is a son of Saudi Arabia's founder, King Abdul-Aziz ibn Saud. The line of succession runs through all of the sons--there were 45 in all--before passing to the next generation.

Fahd showed an early flair for politics and was named education minister in 1953, where he helped introduce education for young women throughout the kingdom. He served as interior minister from 1962 until 1975.

The portly Fahd also earned an early image as a playboy for trips to the French Riviera and to gambling clubs in London. He was said to have given up heavy drinking when he became crown prince, however, and began studying briefing books to learn his new job.