He became chairman of the PLO in 1969. The organization, established in 1964, had hitherto been controlled by Egypt and never been taken seriously. But Mr. Arafat made it into an umbrella organization for Fatah and a half-dozen other guerrilla groups.
With headquarters in Amman, Jordan, the PLO conducted raids in the Israeli-occupied West Bank and Israel proper. It also made Jordan the prime target of Israeli reprisals and threatened the throne of King Hussein. The king's Bedouin army defeated the guerrillas in September 1970 in battles fought in the streets of Amman, a war the PLO called Black September.
It forced Mr. Arafat to move his base of operations to Beirut. From there, he became counselor and blackmailer of the governments throughout the region - assuring them domestic peace in exchange for financial contributions to the PLO. In that way, Mr. Arafat accumulated a portfolio estimated to be worth billions of dollars, paid the salaries of thousands of PLO soldiers and PLO teachers, nurses and bureaucrats, and ensured their loyalty.
Fatah and other PLO groups hijacked airplanes, hijacked buses, took Israeli schoolchildren hostages, and shelled Israeli towns. In 1973, the PLO murdered the U.S. ambassador to the Sudan, in Khartoum. The United States considered the PLO an outlaw.
In 1974, the Arab nations proclaimed the organization to be the "sole, legitimate representative of the Palestinian people` - a phrase that Mr. Arafat repeated as often as circumstances allowed. He used it to claim the status due a head of state.
Many of the threats against him came from fellow Palestinians. During the 1970s and '80s, smaller, more militant groups challenged him within the PLO. They included the Popular Front for the Liberation, led by George Habash, and Nayef Hawatemeh's Democratic Front for the Liberation of Palestine, as well as smaller, break-away factions supported by Syria.
The rare opportunities for peace were usually squandered because Mr. Arafat would not tolerate any challenges to the PLO as the Palestinians' representative. In the West Bank and Gaza, any leader who showed signs of independence from the PLO was intimidated into silence, in some cases by assassination.
Mr. Arafat rejected the 1978 Camp David accords that led to a peace treaty between Israel and Egypt and that included a timetable for Palestinians to be granted political autonomy. The agreement offered substantially the same terms as the Declaration of Principles that Mr. Arafat accepted 16 years later.
In Lebanon, Mr. Arafat sided with Muslim factions against the Lebanese Christians and helped bring about the virtual disintegration of that country. Israel's invasion of Lebanon in 1982 left him besieged by Israeli artillery and aircraft in West Beirut until the United States arranged for his safe passage to Tunis, and the scattering of 15,000 Palestinian soldiers.
He lived in Tunis for the next dozen years. For much of that time, he was flying from capital to capital in search of political support. He continued the habits he began in Beirut of beginning work late in the day and continuing nearly until dawn and for reasons of personal security spending each night at a different address.
To meet with Mr. Arafat - whatever the city in which he happened to be residing - was to wait several hours past the appointed time at night. And then to be whisked by car in the early morning hours to a threadbare office. Mr. Arafat would be warm, elusive, and never without a stack of faxes and other papers and a coterie of bodyguards.
Until the end of the 1980s, his greatest accomplishment was to have offered Palestinians a version of reality that provided more comfort than the one they actually lived. To believe the chairman of the PLO, the Palestinians were militarily strong and advancing, Israel weak and in retreat.
In reality, his reliance on military action had failed. The intifada - the Palestinian uprising that began in December 1987 in the West Bank and Gaza without plan or leadership - was what saved him. The young Palestinians who began stoning Israeli soldiers carried the PLO along on a powerful wave of world sympathy. Mr. Arafat's cause again had the world's attention.
He responded by publicly renouncing terrorism and announcing that he accepted Israel's right to exist. What did not change was his hope of making the West Bank and Gaza an independent Palestinian state.
Mr. Arafat made the PLO into a government-in-waiting. He called himself "President" even though the country he claimed to lead had not been created. But in this way he managed to shelter his cause from manipulations by other Arab countries.
Devoted to work, abstentious when it came to alcohol or cigarettes, he often said he was "married to the Palestinian revolution." It made his marriage in 1990 to Suha Tawil, a Christian from Jerusalem 35 years younger than her husband, all the more surprising to his followers. The marriage was kept secret for more than a year.