FOR YEARS the late William O. Douglas' "brethren" on the Supreme Court were puzzled by the fact that he seldom -- despite his reputation for outspokenness -- said very much during the closed conferences at which only the Justices were present.

Instead, Douglas scribbled constantly, taking what appeared to be verbatim notes.

"We always wondered what he intended to do with them," one of the other Justices said recently.

They need wonder no longer.

He was writing the second volume of his memoirs, which Random House had agreed were not to be published until after his death.

The book, scheduled for late summer or early fall publication, is expected to cause a sensation.

There are predictions that it will be an even greater embarrassment to the court -- a further tarnishing of the image -- than Bob Woodward and Scott Armstrong's best-selling expose, "The Brethren."

Among those who knew previously of the book's existence, the biggest question at the moment is how far Douglas, always the whistleblower, has gone in telling court secrets.

The major part of the book was more or less finished in the early 1970s, at a time when Douglas' bitter battles with Chief Justice Warren E. Burger had gotten to the point where Douglas was threatening to publish a dissent on the abortion issue comparing Burger to the chief justice of Russia.

Three associate justices -- William J. Brennan Jr., Thurgood Marshall and Potter Stewart -- considered Douglas' threat a "form of treason" and pleaded with him not to undermine the court's credibility with the public.

Douglas relented at that time.But his editor, Charlotte Mayerson, gives hints that everything Douglas thought and felt about Burger and the rest of his "brethren" is going to be revealed in his final memoir.

"This is his judgement . . . of the kind of people they were . . . of the kind of performances they gave on the court," she said last week.

There are indications that they may be a difference of opinion over who has final editing control of the manuscript.

Douglas' widow, Cathy, says she is his "literary executor." A source close to Douglas who worked with him on the book up until 1977 said last week that it is his "impression" that "Mrs. Douglas, herself, will do the final editing."

If that is the case, there are those who anticipate that Cathy Douglas, a young, ambitious lawyer herself, will be anxious to avoid controversy. Reached in Florida last week, where she is vacationing, she described the book in terms of "good feelings", making it sound bland.

There could be a fight shaping up when Douglas returns to Washington if she attempts to put her own imprint on the manuscript.

"The manuscript has been turned over by the author to his publisher," Mayerson said last week. "No one will do the editing but me."

Locked for awhile in a safe, the manuscript is now being distilled from more than 1,000 pages to a more wieldy 500-600 pages.

Ironicallay, it was Random House which had the most to lose immediately on the Supreme Court's government secrecy opinion, issued last week.

Random House is the publisher of former CIA official Frank Snepp's book, "Decent Interval," about his experiences as an intelligence operative in Viet Nam, and was preparing to publish further Snepp writings.

In an opinion that injoined Random House from other books "in concert" with Snepp, the court also gave the government broad new powers that would restrict not only intelligence operatives but other employes, including those of the Supreme Court, in what they can publicly disclose.

The opinion, viewed by many lawyers as an attempt by the court to plug its own leaks, is not believed likely to apply to the Justices themselves.

Sharing a limousine home from a party recently, the Kennedy Center's Roger Stevens began grumbling to his fellow passengers about the media and how unfavorable reviews had recently hurt his revival of "Westside Story." From the back seat came the voice of NBC's vice president of news for politics and special programs, Gordon Manning: "Don't blame me, mister," he said. "I just write a 'stamps and cats' column for a weekly newspaper."

Not only did the U.S. Labor Party's democratic presidential candidate Lyndon LaRouche have his bodyguards trained at the country's best-known anti-terrorist school in Georgia, he also hired an "advisor" to travel with his security team for awhile at $1,000 a day plus expenses to teach them tricky on-the-road protective maneuvers. On one trip to Washington the entourage had booking clerks gnashing their teeth at Washington hotels where space is usually tight.

One trick they were taught to throw off the enemy is to make reservations at several hotels at the same time and they stay at one where registrations were made in someone else's name.

"Koreagate's" Tongsun Park had hoped to use old friend Ken Crosby and his new bride as the social "bait" to stage his party-giving comeback here at The Georgetown Club March 5. The Crosbys were asked if other guests could be told that the little get-together was going to "feature" them. It was the same device Park used when he once "featured" House Speaker Tip O'Neill on his birthday to lure top political VIPs. The crosbys first said yes. Now, an aide said last week, it looks as if "they're going to be out of town."