What was going on when I was born?

The Grand Imp settled himself in front of a piece of apple pie and a cup of coffee. A long night of mischief lay ahead and he needed to fortify himself. Between bites, an anxious bystander slipped in quietly next to him. ''Have the demons and dybbuks arrived?'' he was asked. The Imp smiled. His bright blue eyes narrowed. ''For the time being,'' he said, ''I see only people, but most probably the others will show up.'' Isaac Bashevis Singer - Nobel Laureate, master storyteller and literary imp - came to a great Gothic stone church in this suburban community Sunday to attend a stage adaptation of his short story ''Gimpel the Fool'' and later to hold a dialogue with the audience.

An official of the New York City Transit Authority charged with illegally taking benefits from companies doing business with the authority said yesterday he ''thought there was nothing wrong with it'' because other officials were doing the same. The official, Edward O'Grady, testified at his trial in Federal District Court in Brooklyn. He is charged with accepting total benefits valued at more than $30,000 over a 10-year period from 12 companies involved in a contract to produce subway cars for the city.

The Supreme Court agreed today to decide whether the use of home video recorders to tape television broadcasts violates Federal copyright law. The issue is the focus of a high-stakes legal and lobbying battle between the growing video recording industry and the entertainment industry, which calls home video recording ''piracy'' that shrinks its paying audience and threatens its profits. The entertainment industry won the previous round when a Federal appeals court in California ruled last October that the use of the machines, even by individuals in their own homes, infringed the copyrights on the movies and television programs. Since then, both sides have been pressing, so far in vain, for a Congressional response. The video industry seeks a bill to ''decriminalize'' home recording by writing an exemption into the copyright law, and the entertainment industry wants compensation in the form of a tax on the sale of recording machines and tapes.

Israeli tank columns completely cut off Moslem western Beirut today, trapping the military and political leadership of the Palestine Liberation Organization. At the same time, other Israeli armored units, greeted by rice and flowers from sympathetic Lebanese Christians, began driving still deeper into Lebanon, apparently in an effort to push Syrian troops northeast of the capital into the Bekaa Valley. There is a concentration of Syrian troops in the Khalde junction area on the coastal highway south of Beirut near the airport, and fighting was reportedly continuing there today between Israeli forces and Palestinians and Syrians. The Israeli radio quoted Israel's Chief of Staff, Lieut. Gen. Rafael Eytan, as saying that Israeli troops had trapped guerrilla forces in Beirut and that the troops' mission was to smash the P.L.O.'s political and military nerve center there. (Page A18.)

The Government issued a new set of antitrust guidelines in an effort to reduce uncertainty over what kinds of corporate mergers it will allow. Though the new policy was described as more lenient, the Justice Department and the F.T.C. said they doubted that any significant increase in mergers would result. (Page A1.) The Supreme Court will decide whether taping television broadcasts on home video recorders is a violation of Federal copyright law. The issue is at the heart of a high-stakes battle between the video recording and entertainment industries. (D1.) The Court invalidated Alaska's plan to redistribute its oil revenue windfall among its citizens on the basis of their length of residence. (A27.)

A lack of consistent long-range goals and financial support, coupled with rising foreign competition, is seriously threatening United States leadership in nonmilitary space technology, according to a report released yesterday by the Congressional Office of Technology Assessment. The report carries a warning that unless the civilian space program is overhauled and revitalized with a larger commitment of public and private resources, the nation stands to lose significant revenues as well as prestige and influence in this decade, primarily to the expanding Western European and Japanese programs. Despite the successful introduction of the American space shuttle, Japan and Western Europe, largely through the 11-nation European Space Agency, ''soon will be providing stiff competition'' in areas previously dominated by the United States, the report stated. These include rocket launching services, communications satellites and craft for land remote-sensing - all activities with commercial and practical promise that are generally labeled space applications.

Responding to an array of negative developments, prices of Government securities fell sharply yesterday, sending some yields to their highest levels since late February. The Treasury's bellwether 14 percent bond due in 2011, offered at 100 28/32, fell 1 3/8 points, to yield 13.88 percent. As recently as May 11, it had traded as high as 107, during a burst of optimism in the credit markets, returning 13.04 percent. At the outset of trading, the market had to contend with a greater-than-expected increase of $1.5 billion in the nation's basic money supply, as reported late Friday by the Federal Reserve. That announcement left the closely watched measure of money circulating in the economy higher than the Fed's short-run and long-run targets and dashed hopes that the Federal Reserve might ease monetary policy, allowing interest rates to drop.

The Government, seeking to reduce uncertainty about the types of corporate mergers that it will allow, today published a new set of enforcement guidelines ''more lenient'' than previous antitrust policy. Nevetheless, the Justice Department and the Federal Trade Commission, which share antitrust responsibility, said they did not believe that their long-awaited statements would lead to any significant increase in mergers, which have diminished in recent months. Attorney General William French Smith described the new guidelines as an ''evolutionary change - not a revolutionary change'' from actual practices in recent years. William F. Baxter, the Assistant Attorney General in charge of the antitrust division, said that, ''in general, the new guidelines would have to be regarded as more lenient.'' But he added that he did not expect them to encourage more corporate combinations than guidelines that have existed since 1968. Antitrust experts said the new guidelines were more than anything a reflection of current merger practice.

The book review yesterday of ''A Man's Life,'' by Roger Wilkins, incor- rectly described a 1973 Pulitzer Prize that resulted from the Watergate case. The award, for meritorious pub- lic service, went to The Washington Post.

The Reagan Administration, for only the second time, intervened today in the international currency markets in an attempt to smooth out what it called ''disorderly markets,'' according to Treasury Secretary Donald T. Regan. The dollar rose today to new highs against the newly devalued French franc and Italian lira, but it was not immediately clear if this was the reason for the intervention. While Mr. Regan confirmed that the Treasury was authorized to trade dollars to smooth out the market, he said, ''We never reveal how or what or why we intervene.'' The move follows the weekend realignment of currencies linked in the European Monetary System and comes just after an accord was reached at the seven-nation economic summit conference at Versailles, France, in which the United States agreed to study whether there is more need for it to intervene.

Along the battered Lebanese coast, in the wake of the invasion, white flags still fly. They flutter from the antennas of cars without windows or windshields. They hang from bamboo poles stuck into the shell-pocked roofs and verandas of concrete houses. Even some pedestrians carried torn strips of white cloth to signify their neutrality, their surrender to the storm of war. The Israeli Army warned residents of Lebanon's picturesque coast to leave their homes before the bombing and shelling began, and many followed the instructions on leaflets dropped from planes.

There is hardly a sector of the economy now that has not been stymied by high interest rates. But there is no agreement on how to bring them down. Congress wants more money growth, in exchange for lower deficits, while the ''monetarists'' contend that such growth would just push interest rates up by reigniting fears of inflation. At the center of the dispute, as always, stands the Federal Reserve Board, and the Fed, faced with a continuing sharp recession, is in the tightest corner it has been since its chairman, Paul A. Volcker, set his anti-inflation course in October 1979. Mr. Volcker and other governors of the Fed, according to interviews with members of the policy-setting Federal Open Market Committee, contend that they have very little room to maneuver in and, at each turning point, face the risk of prolonging the recession, thwarting the recovery or losing much of the ground that has been gained on inflation.