Eliahu Ben-Elissar, former spy, was walking the crowded streets of Cairo in December 1977, shadowed by a Palestinian assassination team dispatched to Egypt to gun down an Israeli negotiating team and put an end to President Anwar Sadat's embryonic peace initiative.

Colleagues of Ben-Elissar, who is now chief of staff in Prime Minister Menachem Begin's office, recall the former intelligence agent's remarkable coolness as he plunged into crowds in Cairo's teeming downtown, seemingly oblivious to the danger.

When the assassination squad later was caught by Egyptian security police and the plot was disclosed publicly, one Ben-Elissar's aides asked if he had known about the danger to himself and the others in the Israeli party.

Ben-Elissar shrugged his shoulders, smiled enigmatically and replied, "We took all the precautions that were necessary."

The scarcely noticed footnote to the Israeli delegation's first trip to Egypt is characteristic of the measured, self-controlled and coolly analytical personality of Ben-Elissar who, according to informed sources in Begin's inner circle, has the inside track to succeed Moshe Dayan as Israel's sixth foreign minister.

Given Israel's special client relationship with the United States and its constantly spotlighted role in the world arena, the Foreign Ministry portfolio is the most crucial in Israel's 20-member Cabinet. And Begin, who temporarily took the job into his own hands when Dayan abruptly resigned last month, appears in no hurry to appoint a successor.

Interior Minister Yosef Burg and Deputy Prime Minister Yigael Yadin already have turned down the job, meaning ministers of the National Religious Party and the Democratic Movement, respectively, are not likely to accept the Foreign Ministry portfolio. The Liberals, who have a major role in the coalition, do not appear to have any qualified candidates.

Parliament Speaker Yitzhak Shamir, who wants the job, is a possible choice from Begin's own Herut Party, but to appoint Shamir, Begin's political advisers have noted, would triger a divisive and potentially calamitous scramble for the speakers' post. Supreme Court Chief Justice Aaron Barach has been mentioned, but he enjoys the security of a lifetime appointment, and is seen as unwilling to move.

Appointing Ben-Elissar, informed sources said, appeals to Begin because it would fill the vacancy with a Herut loyalist without shaking up the delicate coalition distribution.

Just as importantly, Begin is said to be acutely aware that most candidates would insists on exerting a major influence on the West Bank-Gaza Strip autonomy negotiating committee, now headed by Burg, and in dealing with the problems in southern Lebannon, now handled by Defense Minister Ezer Weizman.

Ben-Elissar, 47, as a Begin protege and proven loyalist, sources said, would be unlikely to pester the prime minister for the kind of expanded authority and independence that Dayan so frequently sought.

In one of a series of recent interviews, Ben-Elissar summed up his idelogy "Being a Jew and having witnessed in this generation both the destruction and the liberation of Jews, my philosophy is very narrow and almost egocentric -- deliberately so.Zionism is more needed now and more founded it in its original reasons than ever before. So I am happy to be the unfortunate who has to be very egocentric and decide on issues always in the frame of a simple choice."

That choice, Ben-Elissar made clear is survival or destruction. "Today, and for years to come, there is only one goal -- to make a state in which to live, to finish an era during which the state was only a shelter and turn it into a country of attraction."

Ben-Elissar is an urbane, intellectual man who is fluent in six languages, who was educated in France and Switzerland (a doctorate in political science) and who, properly, considers himself a historian. One of his books. "Conspiracy to Genocide," published in Paris, is a bitter chronicle of Western blindness to the destruction of European Jewry.

Born in Radom, Poland, as Eliahu Gottlieb, Ben-Elissar was raised in a conservative and well-to-do home until the Nazi invasion of Poland. His father, an industrialist, died in a Nazi death camp and his mother died also after being kept in a concentration camp in Germany.

At the age of 10, Ben-Elissar escaped from Poland and made his way to Palestine. He was too young to fight in the 1948 war of independence, but in the 1950s and 1960s he served in Israel's intelligence service, the Mossad, apparently mostly in Europe.

"He is a guy with no biography," said a close associate with not much exaggeration. The years from 1956 to 1965 are a blank in Ben-Elissar's life as far as the public record is concerned.

After writing books and working a while as a foreign correspondent, he returned to Israel and joined Begin's conservative movement as director of information of the Herut Party and the Likud Bloc in 1971. He had been brought into Herut by Weizman, Begin's campaign manager in the election.

In the 1977 elections, Ben-Elissar ran for parliament and, although widely expected to win a seat, he lost.

Along with Begin, Ben-Elissar is regarded in Israel as a hard-liner, a staunch advocate of Israel's right to settle anywhere west of the Jordan River and an outspoken backer of eventual Israeli sovereignty in the West Bank and Gaza Strip.

Of the 1.1 million Palestinians in the occupied areas. Ben-Elissar said in a recent conversation, "We can live with them and they can live with us. I would prefer they were Israeli citizens, but I am not afraid of a binational state. In any case, it will always be a Jewish state with a large Arab minority."

When asked why Israel does not just annex the West Bank, Ben-Elissar replied, characteristically, with a counterquestion: "Why not extend Israeli sovereignty over Judea and Samaria?" he asked, using the Biblical terms for the West Bank.

"The real sacrifice Israel made at Camp David was not to give up the Sinai, the oil and the settlements there. The real sacrifice was to agree not to extend our sovereignty over Judea and Samaria until the end of the five-year autonomy period, to leave the question of sovereignty open," he said.

While this kind of talk is certain to cause some shudders in the State Department in Washington, it is precisely in tune with Begin and in the politics of filing Cabinet portfolios, that is what counts.