About a year ago Donna Karan, then the designer for the successful Anne Klein collection, stood in front of her closet and shrugged that she really didn't have a thing to wear. It confounded her. "I said, 'Okay, what's wrong? How come my wardrobe is not functioning for me anymore?' "

It's not that she didn't have plenty of clothes, but that "they weren't the right pieces."

She had been working on the Anne Klein II line, and realized that the clothing she was creating for this lower-price division was essentially the way she wanted to dress. "I wanted items to put on as I felt like it -- just like I was making for Anne Klein II. But I wanted items with quality and the feel of luxury."

So six months ago, after crying as she took her final bows with codesigner Louis Dell'Olio at the spring Anne Klein show, Karan started working on her own line. Last month she presented her collection of "clothes and accessories that I myself would wear, the best of everything" to buyers and press.

The show opened with eight models dressed only in black bodysuits and tights, sitting on platforms in Karan's new, unfinished Seventh Avenue showroom. Then the models began adding items: a wrap skirt, pull-on pants, short and long pull-on skirts, a man-tailored jacket, sweaters, gray cashmere pants, scarves (wrapped around the hips), sexy cashmere dresses, chunky matte gold jewelry and more.

All the things that had been missing from Karan's closet.

It was a pure collection of fundamental pieces in the best fabrics. And it was clear from the overwhelming applause at show's end that not only Donna Karan but a lot of women want to dress this way.

Two days before the show, an ebullient Karan, 36, sat on a window sill in the freshly painted offices that once belonged to Halston, a designer she always admired and whose clothes at their best were in the same spirit as hers today. She had removed Halston's mirrored decor and cleared the windows of shades to get as much natural light as possible. "Where I worked at Anne Klein," she said, "it was so dark that when I would take clothing out on the street, nothing matched."

The collection, she says, is designed for a very specific, very sophisticated woman who doesn't have time to shop. "In fact, she hates stores. She must wear clothes. She has to be dressed at all times. She needs them for work, she needs them for theater, she needs them to entertain at home, she needs them to travel -- she's on the go constantly -- and what is a better way of traveling than separate pieces that you just throw on? It offers endless possibilities.

"They are separate pieces that just work. I mean, you could do almost anything you want to them. They're not about fashion, they're not about what is new this year. It's the foundation of a company -- from this plateau we're going to build."

Karan starts with black, "the epitome for me of elegance and sophistication."

"Black is the foundation of every woman's wardrobe, because she can go from day to evening. Besides, I don't believe a woman ever has enough good black pieces in her wardrobe. And I think she's much more apt to try a new silhouette in black before she'll try it in any color. If it's a color, she'll say, 'Oh, I want that color.' If it's black, she'll look at it as a silhouette."

And black goes easily with everything. "I think the way women live today, she has to be prepared to make the fastest change, to feel totally different, and I think that's the whole key in modern dressing."

When Karan says "fast," she's not kidding. Over a black crepe jersey bodysuit she'll add a black knit skirt or pants that pull on in an instant, or a skirt that wraps around the body as easily as a scarf -- in fact, sometimes it is a scarf.

She shows both long and short skirts, preferring long ones with boots in the winter, "then when I go out in the evening I put on heels and wear short . . . it's sexier." Everything she's done for daytime wear she also does for evening. The wrap skirt, for example, in wool for day, is dipped in sequins for night. And while her designs appear lean, solely for the rail-thin, Karan insists they are not. "I make all the clothes on my own body first to make sure that they work," she says, "even with my size 12-14 hips."

There are sweaters and shirts for those who don't like the bodysuit, but Karan is sold on it. "Everything comes out of what works for me -- at home, I live in a leotard. I have a problem when something is too leggy, too revealing, too anything. I like to feel that my body is secure, and then from there I can add everything."

In addition to panty hose, belts, gloves, bags, scarves, even hats, she offers chunky but simple 24-carat-plated jewelry made to complement the clothes. (She can't wear her own jewelry -- she's allergic to everything but solid gold.) And she is insisting that retailers sell all of her designs in one location, a "shop within a shop."

"All the pieces a woman needs will be there," she says. "She won't have to worry about running upstairs and downstairs to find what she needs."

The stores seem to be going along with her "shop" concept, but are less receptive to another innovation -- women's jackets sold in varying lengths like men's. "I don't believe a woman can fit properly into a jacket sized only by the shoulders. Every woman's waistline is in a different place," says Karan, who is grading her jackets not only in regular sizes but in proportions, every size available in both long and short. "If you are spending that kind of money on a jacket, it should fit."

Some pieces, such as a jersey pull-on skirt, will be priced at under $100, but others will go way up. The superb jackets in fine menswear fabrics, for example, one with a fly front and cardigan neckline, another with flange details, will be tagged at $400 and $500.

When she decided she needed gray items in the collection, Karan asked herself, "Why would anyone need my gray flannel?" and chose gray cashmere instead. And when she was offered two qualities of cashmere for a boy coat, another item she dreamed of owning herself, she asked what the difference would be and was told $1,200 versus $1,600 a coat. "I figured at that point price didn't matter," she says, "and went for the best."

And it works. Says Mara Urshel, a senior vice president of Saks Fifth Avenue in the audience at Karan's show, "It was the most refreshing thing I've seen in sportswear for a long, long time. Almost bordering on the verge of couture. Very directional. And now I'm looking for a place with exercise machines."

Adds Saks' fashion director Ellin Saltzman, "It was spectacular, understated, elegant, perfection. Not easy to wear, but well worth the effort."

Donna Karan grew up in the garment business. Her father, Gaby Faske, who died when she was 3, made custom suits for men. She remembers watching the Macy's Thanksgiving Day parade from his office. And she remembers too that her mother, who worked in designer Chester Weinberg's showroom, had impeccably cut blazers in every color made for her by her husband. "It may be why I love blazers so much," Karan says.

She was a terrible student. "I never went to school. I preferred fashion, making my own clothes. I would hang out in the art department, and never went to my academic classes." From age 14 she worked in a shop near her home in Cedarhurst, Long Island. "I grew up in retail," she says.

With Weinberg's help she got into the prestigious Parsons School of Design, but on probation. She never missed a day of class. She worked after school for young designer Chuck Howard and made sketches for Liz Claiborne, then a dress designer.

It was Howard who in 1968 pushed the teen-ager to go see sportswear designer Anne Klein. She remembers wearing her best John Anthony pin-stripe suit and a white fedora and carrying her portfolio. "Walk for me," Klein ordered. "Why should I walk for you?" Karan asked. "Your hips are too big for a model," Klein said, dismissing her. "I know my hips are big, but I'm here for a design job," Karan insisted.

Klein hired her and urged her to quit school and work full time, which she did -- until Klein fired her a short time later. "I just couldn't get it together," she says, pushing her hands through her black hair. "I was 18 years old, and I don't think anyone lasts on their first job. The shock of school and then reality."

She worked briefly for designer Patti Cappalli, who "got me thinking as a businesswoman," Karan says. But after traveling to Europe to see the fashion markets, she realized that "fashion was not going to be the only thing in life that would be important to me. I quickly got married, got my act together and a year later called Anne Klein and asked if I could come back to work. I was 19. I felt very badly when Anne fired me. I had to complete it with her."

She worked in the design studio with Klein, then began scouting fabrics in Europe with Julie Stern, now president of her company. She was still on the road when she was eight months pregnant, and she was back at work a week after the baby was born.

Upon Klein's death Karan was appointed designer for the Anne Klein collection, and she asked her Parsons chum Louis Dell'Olio to help her. "We were the suburban commuters at Parsons," she says. "One day we would have lasagna at his house, the next day he would have matzo-ball soup at mine. I would sew his clothes and he would draw mine -- he is an incredible illustrator. We grew up as friends always wanting to work together."

Dell'Olio now designs the Anne Klein collection on his own. Both he and Patti Cappalli were at Karan's premiere show, all of them hugging and crying as the audience of store executives stood up.

And cheered.