It took Thomas J. Watson Jr., former chairman of International Business Machines Corp., 76 years to come to terms with his father, Thomas Sr., the autocratic founder of the computer colossus.

Retired from IBM since 1971, the younger Watson has put together a frank and revealing picture of Big Blue, the nation's dominant computer manufacturer, and a vivid inside look at the family that dominated its years of spectacular growth.

On one level, ''Father Son & Co.: My Life at IBM and Beyond,'' published by Bantam Books last week, is about the difficulty of turning a clumsy punch card tabulator into an electric typewriter and finally into a computer that can handle tasks from clerical work to complicated defense electronics.

From 1956, when the younger Watson became president of IBM, to his retirement because of a heart attack in 1971, IBM grew tenfold, from $650 million in sales to $7.5 billion. In just the first five years of his reign, the price of IBM stock quintupled, helped by the company's market dominance: in 1961, 4,000 of the 6,000 computers in the country belonged to IBM.

Yet it was not easy going. For example, the famous IBM 360 computer was launched onto the market in 1963 without the software being finished, a terrible risk that could have been catastrophic. And Watson Jr. admits there was a ''dangerous cutting of corners'' because the 360 computer wasn't really ready for the market. But the need to beat the competition at any price prevailed.

On another level, ''Father Son & Co.'' is a moving tale about the emotional struggle between the elder Watson and his son, former ambassador to the Soviet Union during the Carter administration. Their arguments were ''addictive'' to both and ''savage, primal and unstoppable,'' the younger Watson writes.

''Undiluted T.J. Watson could be pretty hard to take,'' he writes about his father, who put his photo in every corporate office and made his aides sometimes wait days to see him. ''I never declared myself winner in the contest, though we fought about every major issue in the business.''

Yet the tense and potentially destructive rivalry with his father does not prevent Watson from explaining that he wrote this book because ''I'm trying to characterize the greatest man I ever knew. I have yet to find a man who can better him across the board for the ability to engender affection and loyalty.''

Watson was interviewed about his new book in the New York office of Bantam Books.

Q. What were your father's main contributions to IBM?

A. He saw the potential of the punch card business. Then he took the business overseas starting in 1918, which gave it a tremendous head start in Europe. Lastly, he had a very enlightened personnel policy. Once he announced a 10 percent cut in pay, but arranged for a band to play during it, and the result was cheers.

Q. What was the turning point in his career?

A. Father was such a naive kid who never finished school. He didn't know an antitrust law from the man in the moon. But old man Patterson, the founder of National Cash Register, asked him to take over a chain of stores selling secondhand cash registers. This experience showed him the promise of the business, but also got him indicted. {The federal government indicted the elder Watson and National Cash Register's senior officers for allegedly trying to create a monopoly. He was not convicted and the case eventually was dropped.}

Q. Should you get credit for taking IBM from the era of punch cards to computers?

A. Well, I saw the need to process information faster. To be fair, the pressure came from customers like Met Life and Time Inc., who couldn't process their accounts fast enough with punch cards. We weren't leading them. They were leading us.

Q. Why did IBM pass the competition by?

A. Father was interested in building a business. He used to say, ''I'm no genius. I'm smart in spots -- but I stay around those spots.'' Our competitors, like Remington Rand, were interested in buying other companies in farm equipment and electric razors. Rand never exploited his machines. ... I was scared when General Sarnoff {founder of RCA} called me and asked us to license the patents. But I agreed, and they never got close to us.

Q. You admit that the antitrust suit against IBM's 70 percent market share had merit and that you were never totally comfortable about destroying the evidence developed by Control Data in its antitrust suit. {In 1969, the federal government -- and later, Control Data and several other computer makers sued IBM, claiming its huge market share was a monopoly. Control Data settled out of court; the government's case was held in abeyance and finally dropped under the Reagan administration in 1981.}

A. Bromley {Bruce Bromley, senior partner of Cravath, Swaine & Moore} had me destroy it before the government came in and subpoenaed it. If I hadn't given the order to burn it, the government and our other competitors could have used it against us. Later, Marshall {Burke Marshall, former Justice Department official under Kennedy} wrote rules of conduct for all the salesmen ... and I felt pure as the driven snow.