A story in yesterday's Style section incorrectly described an agreement between Harper & Row and a free-lance reviewer for The Washington Post. Instead of an oral agreement, the reviewer signed a letter promising to keep the manuscript of David A. Stockman's latest book confidential in order to receive an advance copy. Unlike letters to other reviewers, this one did not include an agreement that Harper & Row would "suffer significant losses" if the manuscript were released before its April 23 publication date.

Already the testing seems to have begun for journalists in the running for a ride on a space shuttle.

In recent weeks, 100 letters went out to reporters around the country telling them that they had made the first cut -- chosen from 1,703 applicants. However, the catch was that they were also told "in stern tones," as one put it, that they were supposed to keep it secret.

The effort to keep journalists quiet, however, runs so much against the grain of people in the business of spreading news that some saw it as an effort by judges to test their self-control.

Officials with the Association of Schools of Journalism and Mass Communication, who are doing the early screening for NASA, have said the reason for all this secrecy is that letters are coming out at different times in different sections of the country.

Said Richard R. Cole, president-elect of the organization of journalism schools: "It also gives them an opportunity after the [space shuttle Challenger] tragedy of saying whether they still want to be in the competition. It is a form that allows them to check yes or no and they don't have to say why."

Journalists who are still in the running said they had to think more seriously about whether they still wanted to go up in the shuttle, and at least one of the semi-semifinalists told his editor that he had to back out for family reasons.

As of yesterday, however, some of the bigger names had not received their letters of congratulations. Sam Donaldson of ABC News said that so far the mailman had not come through. NBC anchor Tom Brokaw, who said he is "still very eager to go," also said no letter has arrived as yet. At CBS, a spokesman said Walter Cronkite was on his sailboat and could not be reached.

Among those believed to have made the first round are John Noble Wilford, the only candidate sponsored by The New York Times; Stan Grossfeld, a photographer with The Boston Globe; Storer Rowley of the Chicago Tribune; Washington Post reporters Mary Thornton, Boyce Rensberger, Kathy Sawyer and Jay Mathews; UPI audio reporter Rob Navius; NBC News radio reporter Jay Barbree; and Jim Slade of the Mutual Broadcasting System.

The official announcement is expected later this month. The journalism organization will select five finalists, perhaps as early as this fall, according to some of those affiliated with the program. NASA will make the final choice.

However, this first round has already triggered new shudders of concern among many journalists about whether their reporting will be compromised by being in a long competition ultimately controlled by the agency many of them are writing about.

Says Eric Engberg, a CBS correspondent covering the NASA shuttle disaster and not competing to report from the skies: "We don't have a journalist in the White House program; we don't have a journalist in an agriculture program. This is just an effort . . . to get a journalist on their team."

Chicago Tribune Editor James Squires said that after the shuttle disaster he suddenly found out that many of those covering the issue had also applied to go up in space.

"We had the damnedest philosophical debate here -- it lasted damn near all afternoon," Squires said. "Ultimately we concluded it was not unlike a pool, and we participate in pools as long as they don't censor what you write."

"It's going to be just plain uncomfortable," one of those in the running acknowledged, but added quickly: "I still really want to go."

Speaking of keeping secrets, one of the standard ways of trying to drum up interest in a big book is to keep it under wraps.

Thus the latest top-secret manuscript, to be published officially on April 23, is David Stockman's book, "The Triumph of Politics: Why the Reagan Revolution Failed," from Harper & Row. The book, for which Harper & Row paid a whopping $2.4 million, is now touted as being so newsworthy that only a few review copies are out and those only to publications that have signed letters not only promising to keep the book secret but agreeing that "Harper would suffer significant losses" if they don't.

"I signed the agreement," said Jack Miles, book editor for the Los Angeles Times, who said his reviewer received the book in mid-March.

And if the L.A. Times news department asked for a copy of the book? "I wouldn't give it to them," Miles answered.

"Only in book publishing do journalists feel that they have a right to what is in a book a few weeks before it's going to be published anyway," Miles said. "It's outrageous, a deplorable waste of journalistic talent that could be used for other more important stories. It's not journalism. Everyone knows that they will be able to go to a store and buy this in short order . . . "

The opposing view came from Mitchel Levitas, book review editor of The New York Times, who says he never got the letter because he told a Harper & Row executive in advance that "if I got a copy, I would not and could not withhold it from the news department.

"The policy of the paper is that if we get something that's a story, I'm not going to sit on it," Levitas said.

At The Washington Post, editors refused to sign the confidentiality agreement but allowed the publisher and the reviewer to work out a verbal understanding so that the reviewer would have the book a few days before the publication date.

Publishing insiders say Harper & Row has been particularly nervous about what some publishers see as a tendency for newspapers to allow their news staffs to break embargo dates.

But book editors at several newspapers said they routinely see book editors trying to pump up excitement for a book by making it scarce.

"I don't understand all the security hype from Harper & Row," said Post Deputy Managing Editor Richard Harwood. "Obviously, this is an attention-getting device. It's not as if he were publishing the contingency war plans of the Pentagon."

The first excerpts, purchased by Newsweek for a reported $250,000, are expected to appear in issues that are available April 14 and April 21 -- more than a week before the book is available.

"With a news magazine excerpt, you have no idea about what supporting evidence or other detail there is," says Thomas Oliphant, who will analyze the Newsweek excerpts and the book for The Boston Globe. "In Stockman's case it is so important. What is at issue here is not his brilliance or his policy recommendations, but his credibility. In the last few years, most reporters have known that if David Stockman tells you the sun is shining, you better look out of the window before you write it."

Daniel G. Harvey, who is in charge of promoting the book for Harper & Row, said, "This book is of enormous news interest, and its value to Newsweek is in its being fresh," he said. "If it is released and in the hands of anyone who wanted to draw from it, it would have less news value."