It was the decade of decadence, peppered with lonely, beautiful, popped-out people who were on a first-name basis with mood elevators and down discolators: Andy, Liza, Bianca, Mick, Viva, Truman, Halston, Calvin. And Bob. Bob?

"As I was writing this, I couldn't believe I did this, we did this," says former Interview magazine editor Bob Colacello. "On the other hand we did have a lot of fun. The great thing about the '70s was that society was very very open. It really was transvestites and socialites and tycoons and titles and beauties and brains and gays and straights. As long as you brought something to the party, you could come to the party." And what did Bob bring?

"A big mouth." At 43, the dapper kid from Brooklyn is still dishing, having just published his long-awaited "Holy Terror: Andy Warhol Close-Up," a bitchy, bittersweet memoir of his 13 years as the pasty-faced pop artist's puckish alter ego. He was Costello to Warhol's Abbott, Watson to Warhol's Holmes, Elmer Fudd to his Daffy Duck.

"We were a team," he says.

Sitting in an alcove in the Jefferson Hotel, Colacello looks every bit the graduate of the Georgetown University School of Foreign Service that he is: navy blue blazer, striped shirt, tasteful tie, pressed blue jeans and loafers. His dark hair is parted neatly on the side and the frames of his glasses are thick and serious. He is a small man, with delicate fingers, full lips and a bulbous nose. He is charming, witty and well informed on the foibles of the famous and seems as suited to his job penning highly amusing, often biting celebrity profiles for Vanity Fair as Paul Prudhomme is to blackening redfish.

"I was one of Andy's kids," Colacello recalls, recounting his heady days at Warhol's Factory. "He was an idol of mine. I really did think Andy was the coolest, hippest thing.

"It was pretty dazzling to be 22 years old and suddenly going to Mick Jagger's birthday party. My head was turned. Like a cult guru, Andy did sort of manipulate us and brainwash us. He loved you to drink and take drugs to excess so the next day he could say, 'Oh you don't remember what we did. You embarrassed yourself so much.' "

Colacello, first as a Warhol gofer, then as editor of the artist's fledgling magazine, became a witness to Warhol's social climbing, dutifully recorded in his gossip column for Interview. Much of it now seems rather tame, but at the time no other publication had the entree that Warhol and Colacello cultivated. How many authors can tell their grandchildren they shared a glass of Perrier with Jackie O, a rather thin '70s vignette. (Jackie Onassis called Warhol the following day to chastise him for bringing a gossip columnist to one of her parties. Presumably, he was not invited back.)

Then there was the time Colacello got sick in Halston's sink. "At least it was Halston's sink," says Colacello, "and not some third-rate fashion designer." Rubbing cocaine vials with celebrities, Warhol would get Colacello, at 4 in the morning, to "pop the question," meaning approach people about having their portraits taken as a preliminary to a Warhol silk-screen that would cost them upwards of $25,000 for just one print. It was Bob and Andy. On the road to Europe, L.A. and oblivion. "I was there, for better or for worse. I was the only journalist who was close to Andy."

What Colacello saw was a typical creative genius: selfish, egomaniacal, "a big baby." Colacello writes provocatively on Warhol's relationship with Truman Capote. "My job was keeping Andy and Truman together, dealing with these two big brats." Colacello would hear from both sides: " 'Who does he think he is?' Both were fighting for control. Both wanted to have the final say."

According to Colacello, Warhol was a "very unhappy person" and terminally insecure. Warhol didn't want you to think "you had a real talent." Competition was one reason. Fear of abandonment was another. "Somebody offering us a better job. It was all about keeping control. Andy didn't want us to have any self-esteem. He wanted us to think we were there because of him, and little by little I began to see that sometimes he was there because of us."

Riddled with self-doubt about his looks, Warhol "always felt like the outsider ... inferior, ugly, strange. He knew people thought he was a creep."

Colacello's vivid portrait of the late artist is highly unflattering, and reviews of the book have been mixed. Time magazine called it a "514-page nag" and said that perhaps this book was written in retaliation for Warhol's remarks about Colacello in the posthumous Warhol diaries. "Dueling diaries may be the perfect '80s moment," Time observed, "in which two shallow people recount in mind numbing detail the comings and goings ... of long forgotten and always boring celebrities."

Colacello does have a few words of praise for his old mentor: He calls him "the great artist of the second half of the 20th century." He can't resist adding that Warhol was also "a very complicated, miserable, unhappy, morbid, manipulative, funny, strange, weird man."

Born in Brooklyn, Colacello grew up in Long Island. His father sold coffee in Manhattan and his mother sold dresses at Saks Fifth Avenue in Garden City. "My mother used to make my two sisters and I sit down every day after school and have cookies and milk with her and tell her our days. We all learned how to turn everything into stories and she encouraged us to mimic other students, or teachers. Literally, I would do the same thing at these fancy dinner parties with Andy. He said, 'Tell the Elizabeth Taylor story, Bob.' I'd be off on Elizabeth Taylor in Rome with Andy. And then there'd be the Margaret Trudeau stories, smoking pot in her room."

Warhol's art and life became intertwined. Personalities were courted and silk-screened and sold like giant baseball cards. "What he didn't like was when I started selling myself." Fueled by eight or 10 vodkas a day, Colacello was editing Interview and writing a column. He began to resent Warhol's treatment of him. "I was 35 years old. I didn't want to be called a kid anymore." He wanted to prove to Warhol that he had entree to the rich and famous on his own. He also was told by a doctor that he would die of cirrhosis of the liver if he didn't stop abusing drugs and alcohol. Warhol became miffed, telling Colacello he was "boring" because he wasn't "staying out all night taking cocaine.

"It gets confusing," Colacello says, eyes widening. "What are you supposed to do? Self-destruct so he has better stuff for his diary?"

When Warhol began telephoning his assistant Pat Hackett every morning with his tales from the night before, Colacello was doing likewise, and Hackett was recording them. Dueling diaries may be one way to see it. Dysfunctional pen pals might be another.

"I wasn't in love with Andy. I was perhaps in love with the idea of Andy the artist. ... I was in love with Andy the way nuns marry Jesus. I was brainwashed."

In 1983, after a series of public embarrassments, Colacello walked out on Warhol and, as he writes, "the mindlessness of our merriment."

"It was mindless," he says now. "After Vietnam, people just wanted to party, party, party. And they all came to New York to blow their minds and dance all night and have a lot of sex, let's be frank about it. ... In the '80s, we started to pay the price." Andy Warhol is dead. So are Studio 54 owner Steve Rubell and fashion designer Halston. Edie Sedgwick OD'd and the Betty Ford Center and Hazelden have become the new celebrity watering holes.

How did Colacello escape being another victim?

"I am a victim! Here I am sitting talking about Andy Warhol. I still haven't escaped."

Bianca Jagger is suing the Warhol estate for remarks the artist allegedly made in his diaries. She arrived at Colacello's New York book party, given by Vanity Fair Editor Tina Brown, as the author's date. The party was a mad affair. Pat Buckley was there and Tama Janowitz and supermodels Naomi Campbell and Veronica Webb.

He is asked how Warhol would have liked it.

Colacello smiles. "He probably would have left after five minutes," says the author. "Just to be mean."