Martha Rountree, 87, who helped shape television history and public affairs journalism as the co-creator and first moderator of the NBC News interview show "Meet the Press," died Aug. 23 at Sibley Memorial Hospital. She had Alzheimer's disease.

"Meet the Press," the longest-running network television show in the world, first went on the air in 1945 as a radio show on the Mutual Broadcasting System. It was created jointly by Miss Rountree and Lawrence E. Spivak. It jumped into television in 1947, before there were even 1 million sets in the nation.

On the show, as its name implies, figures from public life submit to the questions of journalists. It set the pace for public affairs interview journalism and became must viewing for the political community. It remains a Sunday morning ritual in many Washington homes and supplies the substance for many Monday morning newspaper stories.

Besides her role in creating the show and with urging its shift to TV, Miss Rountree, a Florida-born former newspaper reporter, was also said to be the only female moderator in its history.

Unrehearsed interview shows with statesmen and public figures, commonplace today, were a novelty on the airwaves when "Meet the Press" began.

"I think it is important that the public should hear its elected officers speak out and take their stand in answer to direct questions without preparation or oratory," Miss Rountree said in 1946.

"There is nothing so refreshing as unadorned conviction."

Among those who appeared on early shows were such significant figures of the mid-20th century as President Harry S. Truman, Sen. Robert A. Taft (R-Ohio) and Henry A. Wallace, who had been vice president during Franklin D. Roosevelt's third term.

Sen. Joseph R. McCarthy (R-Wis.) appeared, as did United Mine Workers chief John L. Lewis and New York Gov. Thomas E. Dewey, who was defeated by Truman in the 1948 presidential campaign.

These were among the most formidable figures of their time, in an age when public life was an almost exclusively male preserve, but Miss Rountree "never felt intimidated by anybody," her daughter Martha Wiethorn said yesterday.

Miss Rountree also produced several other public affairs television shows, including "Keep Posted," "Washington Exclusive" and "Capitol Closeup." The first three guests on "Capitol Closeup" were President Dwight D. Eisenhower, his vice president, Richard M. Nixon, and FBI director J. Edgar Hoover. According to one newspaper account, Hoover was never again interviewed live on the air.

Another of Miss Rountree's shows was "Leave It to the Girls," which began as a radio show in which female panelists sought to give amusing answers to listeners' questions on romance and other matters. In 1960, she was involved in a debate-style TV show called "The Nation's Future."

In a newspaper interview more than 40 years ago, Miss Rountree described herself as a "blunt-speaking, down-to-earth television news reporter, and I'm proud of it."

"She was a news pioneer who helped create a national treasure," said Tim Russert, NBC News Washington bureau chief, who is current moderator of "Meet the Press."

Miss Rountree sold her share in "Meet the Press" and "The Big Issue" to Spivak in the fall of 1953. Wiethorn said the flip of a coin decided who would buy out whom.

Three years later, she brought to the air a new public affairs show called "Press Conference." It premiered July 4, 1956, with U.S. Attorney General Herbert Brownell responding to the queries of 16 reporters.

Martha Rountree was born in Gainesville, Fla., and was brought up in Columbia, S.C. Interested from an early age in writing, she wrote a short story when she was 9 and worked for the Columbia Record newspaper while in college at the University of South Carolina. She left school before graduating and joined the Tampa Tribune as a reporter.

She moved in 1938 to New York, writing advertising copy and freelancing articles to magazines. "Meet the Press" has been described as designed originally to serve as a promotion for American Mercury, a magazine edited and published by Spivak.

On the original radio show, Miss Rountree was moderator and Spivak the permanent member of the rotating panel of journalistic questioners. Spivak died in 1994.

"Freedom of the press is America's first line of defense," she said in a speech in 1950, at a time when civil liberties were seen as under attack. "It is something that must be fought for continuously--not taken for granted."

Miss Rountree was a longtime Washington resident.

A first marriage ended in divorce. In 1952, she married Oliver M. Presbrey, who died in 1988.

In addition to Martha Wiethorn, who lives in Bethesda, survivors include another daughter, Mary Greene, of Duxbury, Mass., a sister, a brother and three grandchildren.

CAPTION: Martha Rountree helped create an array of broadcast news shows.