What was going on when I was born?

More Israeli armored forces poured into west Beirut today, increasing the Israeli grip on the predominantly Moslem sector, and Lebanese Christian militiamen entered Palestinian refugee camps in the southern suburbs to arrest guerrilla suspects. With Israeli tanks standing guard outside, Israeli-backed Phalangist militiamen moved by foot and jeep into the battered Sabra and Shatila camps. Automatic weapons fire could be heard from within, and women weeping hysterically began appearing in downtown west Beirut and saying that their husbands and sons had been been taken away by armed Phalangists. Sharp fighting flared for a time today between Israelis and Lebanese leftist militiamen along the Corniche Mazraa, on the southern edge of downtown west Beirut, where the Mourabitoun militia had its main base. But the Lebanese state radio said the Israelis were soon in complete control.

Developers of the Lincoln West luxury housing project planned for Manhattan's West Side said yesterday that construction could begin on the $1 billion complex by April. The project, which had the active support of the Koch administration, was given final approval yesterday by the city's Board of Estimate. The board's 10-to-1 vote came just before 2 A.M., with the negative vote cast by Borough President Andrew J. Stein of Manhattan, who had encountered pressure from community groups and local elected officials opposed to the high-density plan. The other board members voted as a bloc in favor of the project after a chaotic and politicized meeting. ''I've never seen so many lawyers here,'' Deputy Mayor Robert F. Wagner Jr., who is Mayor Koch's chief negotiator for the project, said after a day and night of talks.

Leon Fleisher, the two-handed pianist, is back, doing again what he once did as well as any pianist in the world. Even a soap-opera fan might have trouble swallowing the scenario. A young pianist, celebrated as one of the young lions of his generation, is mysteriously crippled in the right hand and for 17 years is forced to pursue a career as teacher, conductor and specialist in the meager left-hand repertory. Now, after countless hours of examinations, psychiatric and physiological sessions, an operation and muscle therapy, he returns to the concert stage with both hands functioning and scores a triumph with Franck's ''Symphonic Variations'' for piano and orchestra. Not only that, but with the hall still resounding with cheers, he sits down and plays a Chopin Nocturne as an encore. It is spellbinding. Pandemonium ensues. Strong men brush away tears.

President Reagan today raised the question of whether the Federal Reserve Board should be placed under the authority of the Treasury Secretary. Answering questions at a political campaign appearance, Mr. Reagan said that in the past several weeks the Federal Reserve had been working well. But when the central bank was established, he noted, the Secretary of Treasury was its head, and he asked whether someone should reconsider whether such a system might work better than the current one. Reopens Sensitive Issue He did not elaborate, but the remark revived the sensitive issue of crimping the Federal Reserve's autonomous status in setting monetary policy and influencing interest rates and raised the question whether the Administration might still be considering exercising some sort of oversight over the Federal Reserve.

While White House and State Department officials called again today for an immediate Israeli withdrawal from west Beirut, President Reagan was saying that the Israelis moved in after they came under attack from Moslem forces. The Israelis have made no such assertion, but said they went in to ''prevent the danger of violence, bloodshed and anarchy.'' In Jerusalem, meanwhile, the President's special envoy, Morris Draper, was told by Foreign Minister Yitzhak Shamir and Defense Minister Ariel Sharon that Israeli military officers would meet as soon as possible with Lebanese Army officers to discuss transfer from Israeli to Lebanese control. (Page 4.)

David Dubinsky, former president of the International Ladies Garment Workers Union and an influential labor leader for more than three decades, died yesterday at St. Vincent's Hospital in Manhattan after a long illness. He was 90 years old and lived in Manhattan. With extraordinary flair and boundless energy, Mr. Dubinsky was the major force in converting a union that was on the verge of bankruptcy in 1932 into a dynamic organization that had $500 million in assets in 1966, when he became its honorary president. The influence of Mr. Dubinsky, a short man with gray crew-cut hair, extended well beyond his union. He played a major role in the formation of the Committee for Industrial Organization, forerunner of the Congress of Industrial Organizations, in the mid-1930's; he was the first head of an American Federation of Labor union to demand action against organized racketeering in unions; he pushed labor toward greater social responsibility, and he was for many years one of the forces behind the Liberal Party in New York.

The coalition that has governed West Germany for the last 13 years collapsed today as the Free Democrats pulled their four ministers out of the Cabinet, and Chancellor Helmut Schmidt challenged the opposition to agree to hold new elections. Rebuffing the Chancellor's proposal for fresh elections, Helmut Kohl, the leader of the opposition Christian Democrats, said instead that his party would try to put together a new government with the Free Democrats and then face the voters. Hans-Dietrich Genscher, the Free Democratic leader and former Foreign Minister, made a similar pledge. After weeks of tense bickering between Mr. Schmidt's Social Democrats and the Free Democrats over economic and foreign policy, the breakup of the coalition left the Chancellor momentarily in charge of a minority Government, and it opened a period of uncertainty in West German politics as Mr. Kohl and Mr. Genscher bargained over the shape of the Cabinet they propose to form. Opponents Accused of 'Intrigues' The end of the coalition came early this morning when, alerted to Mr. Schmidt's desire to address Parliament, Mr. Genscher and the other three Free Democrats in the Cabinet - Economics Minister Otto Lambsdorff, Interior Minister Gerhart Baum and Agriculture Minister Josef Ertl - resigned.

Gen. Bernard W. Rogers, the NATO commander, said today that the movement in the United States for a nuclear arms freeze would encourage Moscow not to negotiate an arms reduction. He also renewed his call for increased military spending by America's allies in the North Atlantic Treaty Organization to close the gap with the Warsaw Pact in conventional fighting strength.

Thailand warned the United States and other non-Communist nations today that it would force thousands of Indochinese refugees back to their homelands unless other countries increased their refugee quotas. The National Security Council leader, Prasong Soonsiri, called in the Ambassadors of the United States, Canada, Australia, Britain, France, West Germany, Italy, Belgium and Japan and told them Thailand had no intention of becoming permanent host to more than 175,000 refugess from Laos, Cambodia and Vietnam.

About 25 leftist guerrillas raided a meeting at the Chamber of Commerce headquarters tonight and held two Cabinet officials, the Central Bank president and about 200 business leaders hostage, the police said. The masked intruders, armed with machine guns and rifles, ordered their captives to lie on the floor and gravely wounded a businessman who failed to do so, police spokesman Carlos Quezada Aguilar said. ''The subversives have not yet demanded anything, only that the authorities not shut off water, telephones and electricity to the building,'' he said after officials spoke by telephone to a guerrilla leader inside.

Four men accused of being leftist guerrillas were shot at dawn today in the first such executions since political violence became widespread in Guatemala 20 years ago, the army said.

Before 1,500 mourners in the city of Princess Grace's birth, John Cardinal Krol extolled her virtues today as an actress, a woman of faith and most of all as a mother devoted to her family. ''Grace Kelly will be remembered as a famous Philadelphian, as a talented actress, and as the Princess of Monaco,'' Cardinal Krol told the noontime crowd jammed into the Cathedral of Sts. Peter and Paul. ''But there is an important dimension to her life that merits recognition and remembrance and that is her role as wife and mother.''