The four-section paper was a radical transformation. The first part carried foreign and national news, while two sections were given to metropolitan and business-financial news. The fourth inaugurated a cornucopia of feature sections that were different for each weekday: Sports on Mondays; Science on Tuesdays; Living on Wednesdays; a Home section on Thursdays; and Weekend, an arts and entertainment section, on Fridays.

The Times also introduced four Sunday regional sections aimed at New York City’s affluent suburbs in New Jersey, Long Island, Westchester County and Connecticut.

The changes spurred advertising and feature articles on suburban localities, and on food, gardening, entertaining and other topics. Some critics said pieces on penthouse deck furniture and high-end cooking undercut the paper’s reputation for serious journalism, but defenders said they took no space away from regular news and brightened the tone of The Times.

In any case, the sections proved popular with readers and advertisers, and some media historians called them collectively the most important redesign of the paper since its purchase by Adolph Ochs in 1896.

In 1976, Mr. Mattson announced plans to computerize The Times’s newsroom, and over the next two years writers and editors surrendered typewriters for bulky computer terminals that sped the processing of news.

The last major labor-management dispute negotiated by Mr. Mattson was an 88-day pressmen’s strike in 1978 over demands by The Times, The News and The New York Post to cut the number of workers operating their presses. It ended with smaller staff reductions than the newspapers had sought and cost $150 million in advertising and circulation revenues. But the papers won concessions that insured long-term profitability and eventual control over their own pressroom operations.

Mr. Mattson brought another long-planned project to fruition in 1980: a national edition of The Times, edited in New York and transmitted by satellite to Chicago for same-day distribution in the Midwest. Two years later, The Times began beaming its national edition to California for same-day distribution to major cities in 13 Western states. Two decades later, the national edition accounted for more than half the print paper’s circulation.