Barry Landau, the Jet Set publicist who has said under oath that Hamiliton Jordan tried to obtain cocaine through him at Studio 54, didn't put everything that he says happened that evening into his sworn affadavit.

If Landau writes as candidly as he talks about the superstars of showbusiness and society, his memoirs will be more than just a social climber's guide to collecting famous friends for fun and profit.And to back up what he says about how well he knew certain VIPS, he claims to have a collection of photographs stashed in a safety deposit box.

In New York, Landau is known as "Triggerman" because he went almost nowhere without his Polaroid. After he came forward to sign an affadavit for the Justice Department about Jordan, a lot of Landau's friends and fellow hedonists began calling nervously to inquire about his photo albums.

Almost the only one to offer his congratulations and say how amused he is by it all is Truman Capote, who also owns a Polaroid and has his own famous collection of People magazine personalities at play.

Landau's feelings are hurt because, he says, a lot of people used him to get them box seats and the best tables and invitations to the really fun parties. Now he feels some are dumping on him in interviews, accusing him of hustling them and sponging off them and doing anything to become wellknown where people are so frequently well-known for just being well-known.

Even if the libel lawyers should cut out the X-rated anecdotes, Landau still has plenty of innocently amusing insights into the milieu of the very rich and the very talented and the very powerful.

Some of his reminiscences are not necessarily self serving. He thinks, in fact, that Alice Roosevelt Longworth's granddaughter, Joanna Sturm, may try to take some kind of legal action against him.

"She's already had her lawyer send me a letter forbidding me to see Longworth," says Landau.

Joanna Sturm explodes at the mention of Landau's name. "WHAT do I have to do to rid myself of that man!" she said. "The man is a thief."

"I knew she'd say something like that," Landau responded. "I suppose she is also going to say I stole all the autographed pictures of Mrs. Longworth that she gave me and I have hanging on the same wall."

Framed on the wall of Landau's Manhattan apartment are two plates from the Rose Medallion tea service which was a gift from the Dowager Empress of China to President Theodore Roosevelt's daughter.

Landau says "Mrs. L" game them to him when he was there one afternoon for milk and cookies. "I'm sure Joanna is going to try and get them back when she finds out they were presented to me," he says.

Landau gets very indignant about people who rip off the rich and don't even think of it as stealing because the victims can so easily afford more.

For nine months, Landau says, he served as a kind of unpaid "major domo" for Louis F. (Bo) Polk, chairman of the board and chief executive officer of Leisure Dynamics, Inc.

"People would walk out of there with 4-foot, framed Andy Warhol's under their arm," Landau claims.

Polk lives across the hall from former Secretary of State Henry Kissinger at the expensive and exclusive "River House" in New York. "The floor plans are identical," Landau says, "except that Bo had his 32 rooms remodeled into just nine. His drawing room is 80 feet long now and his bathtub is big enough to hold 10 people."

The fun-loving Polk, according to Landau, kept a kind of Holly Golightly, "Breakfast At Tiffany's" party in progress. It was the envy of the equally gregarious Kissinger, says Landau, who says the star-struck former Secretary once jokingly threatened to fire a bodyguard who kept Cheryl Tiegs from ringing his doorbell in a mood of mischief one 4 a.m.

Kissinger's name is one that Landau drops frequently. Once asked by Andy Warhol to bring a celebrity to a party the artist was giving for newstand distributors of his "Interview" magazine, Landau fell into step beside Kissinger while he was walking his dog, "Tyler," and walked him right into camera range of a mob of photographers waiting with Warhol.

Landau can serve up a lot of Kissinger tidbits on the smorgasbord of celebrity trivia that he dishes out. Henry saying to Landau at the "Superman" premier: "I always KNEW someone would eventually get around to make a film of my life."

Then there's the Shah of Iran telling Landau about a pet seal he once kept in the palace in Tehran and how they learned to communicate by barking at each other. . . And there is First Lady Rosalynn Carter telling Landau that she knows that all his fashion designer friends like Halston think she dresses like "a hick" but that as far as she is concerned "any woman with a sewing machine can make a dress."

Landau has, along with his trusty Polaroid, almost a photographic memory.And the images he recalls could turn into a titillating best seller.