''This year is an extraordinary set of circumstances. It's what I think of as a shakedown,'' says the choreographer Twyla Tharp, who for the first time in 23 years, is without a dance company that bears her name or her singular stamp. This past July, Ms. Tharp announced that she was disbanding the modern-dance troupe she began in 1965 and accepting the invitation of American Ballet Theater's artistic director Mikhail Baryshnikov to join A.B.T. as an artistic associate and resident choreographer, a billing she now shares with Sir Kenneth MacMillan.
Newly ensconced in her own office at Ballet Theater's studios on lower Broadway, the 47-year-old choreographer ruminated not long ago on the challenges she faces in working with a major company not devoted solely to her artistic agenda, as well as on her recent decision to retire from dancing.
Ms. Tharp's arrangement with Ballet Theater - which has taken on seven of the 15 members of Twyla Tharp Dance - has led many to wonder how the choreographer will maintain her creative identity and make her mark within a large established ballet company, and whether Ms. Tharp and Mr. Baryshnikov - forceful personalities in their own right - will develop an environment in which both can thrive.
''I have to find a way of creating an atmosphere within this company that allows me to work with the same concentration and focus that I had with an independent company,'' said Ms. Tharp, wearing a sweater emblazoned with the face of a tiger. ''I'm concerned with developing strong individual personas for these dancers, in making them be themselves-plus, which is something that ballet has traditionally discouraged. The question is, 'How do I make these people very specific as my dancers have always been and yet continue working within this more generalized situation?' ''
Mr. Baryshnikov believes the presence of Ms. Tharp and her dancers at Ballet Theater will stimulate its classically rooted dancers and extend their stylistic range. He also suspects that the choreographer's close association with a major classical ballet company will ''stretch Twyla's horizons'' and bring both the company and Ms. Tharp new audiences. Several of the choreographer's earlier works are to be added to the Ballet Theater repertory.
When asked if he envisions clashing egos, Mr. Baryshnikov allows that a few board members had expressed that concern: ''Twyla is a very tough and determined lady, but she is always reasonable. The most talented people are probably the most difficult to deal with. Everybody has an ego - I do as a director, Twyla does as a choreographer. But we're a good team, and we know each other so well that we don't have to talk at length about anything. We are learning from each other.''
Ms. Tharp's former dancers made their debut as members of Ballet Theater when the company opened its 1988-89 season at the Orange County Performing Arts Center in Costa Mesa, Calif., in November. ''The Fugue'' (1970) and ''In the Upper Room'' (1986) - two signature works created by Ms. Tharp for her own troupe - had their Ballet Theater premieres during that engagement.
For the moment, only former Tharp members dance ''The Fugue,'' whose contrapuntal rhythms are stamped out on a miked stage by three men wearing boots. Both companies, however, perform ''In the Upper Room,'' a ballet to commissioned music by Philip Glass that plays with both the elevation of classical technique and the groundedness of modern dance and is performed in pointe shoes and sneakers. White Tights Versus The 'Stomper' Style
Despite his long-standing friendship with the choreographer, Mr. Baryshnikov is not blind to the potential difficulties involved in this transition. ''I'm concerned about the way Twyla will adjust emotionally to the situation after all those years of being the boss and doing whatever she wanted to do,'' he says, adding that he and Ms. Tharp had explored the possibility of this turnabout for several years. ''Here there is a different structure. She'll have to share programs with different choreographers, and we'll have to figure out how she will use the company. I cannot allow a division within the company. Her dancers are my dancers and vice versa.''
At the same time, he admits he cannot put the majority of her former dancers ''in white tights in the front line of a classical ballet,'' because most of them are not conservatory-trained ballet dancers like those at Ballet Theater. Instead, Mr. Baryshnikov sees them performing character roles in the standard classics and works from the modern repertory - ''which is where they came from,'' he says - as well as coaching Ballet Theater's dancers in what he refers to as Ms. Tharp's ''stomper'' style.
A bold inventor of dance forms, Ms. Tharp has mined a variety of choreographic sources, from vaudeville to ballroom dance to ballet, and has made a name for herself beyond the world of contemporary dance through her works for theater, film and television. Though never a ballet dancer, the choreographer has created ballets for the Joffrey Ballet and the New York City Ballet, as well as for A.B.T. For her own company, she had increasingly recruited ballet dancers as she moved beyond her highly personal vernacular style to embrace the vocabulary of classical ballet.
''The largest contributing factor to this move was my feeling that dancing has become dancing again,'' says the choreographer. ''It isn't modern dance, it isn't ballet. Twenty years ago, it was very different. People went to modern-dance classes or ballet classes. Nowadays, everybody takes the same classes.'' In response to the increasing crossover between the two camps, Mr. Baryshnikov has pursued an artistic policy of choreographic diversity at Ballet Theater. The company has acquired works by the modern-dance pioneers Merce Cunningham and Paul Taylor and, last year, commissioned a ballet by the post-modernist Mark Morris. Now, there is talk of a new work for the company by Martha Graham, who, in an unprecedented appearance, led the Ballet Theater dancers in a class in her technique several weeks ago.
''I think it's very exciting when the choreographer has a totally different background from the classical tradition,'' says Mr. Baryshnikov. ''Because Twyla doesn't have a formal classical technique, she has much more freedom. She is free of cliches.''
Shelley Washington, a veteran of 14 years with Ms. Tharp and now a Ballet Theater member, recalls her apprehension about her new posting. ''I never thought I'd be a part of A.B.T.,'' says Ms. Washington, who is oriented in modern dance and has been coaching the Ballet Theater dancers in Tharp technique. ''At first, I wondered how I would find my place there. Then I thought, 'Where else would I get to dance Tharp, Taylor and Cunningham?' '' The Dilemma: Making Dances or Money
In the past two years, the financial, administrative and touring obligations of Twyla Tharp Dance had become too much of a burden for Ms. Tharp, who says she found herself devoting more time to fund-raising and running her company than to making dances or developing dancers.
The choreographer had frequently looked for antidotes to touring by incorporating her dancers into most of her commercial projects. She created the dances for three films directed by Milos Forman - ''Hair'' (1979), ''Ragtime'' (1981) and ''Amadeus'' (1984) - and, in 1985, made her debut as a Broadway director and choreographer with the critically assailed ''Singin' in the Rain.''
It was following what she calls ''that Broadway experience'' that Ms. Tharp decided to shift the focus of her company in order to work more strictly within the vocabulary of classical ballet. After the show's five-month run, many of her veterans retired, some were let go; five stayed on. She then hired 10 new dancers, the majority drawn directly from ballet companies.
While there was no deficit in her company this year, said Ms. Tharp - who has long been committed to the uncommon practice of keeping her dancers on a 52-week salary - the troupe had been spending up to seven months on tour during each of the last three years to meet its $2.5 million budget. The heavy touring took its toll: In June of 1987, seven of her 15 dancers left the company. Several of them had hoped to work closely with Ms. Tharp - who rarely went on tour, in large part to work in the studio and to pursue other interests - and became disenchanted with the lack of new work; others moved on to do their own choreography.
''Twyla is not like a Merce Cunningham, who loves to tour with his company,'' says Mr. Baryshnikov, ''or like a Paul Taylor, who can work year by year the same way, making dances in the fall, touring, doing a spring season in New York, off in the summer. So, I said to her, 'Let's see how we can help each other.' ''
Ms. Tharp, in turn, says: ''When I look at the people who are the guiding figures in modern dance, I think, 'This does not look to me like the way I want to spend my days.' Unless a situation has a lot of potential for change and development, I don't think it's very interesting beyond a one-shot deal, which is one of the problems with the whole modern-dance structure. There were many, many conflicts that really tore at me, but when fund-raising becomes your primary job, then you have to take some steps.''
Ms. Tharp's and Mr. Baryshnikov's artistic alliance took root in 1976, when Ms. Tharp created ''Push Comes to Shove,'' a send-up of ballet's hierarchy that provided a comic and decidedly American persona for Mr. Baryshnikov. A popular hit, the ballet was Ms. Tharp's first for both Ballet Theater and the Russian-born dancer.
After Mr. Baryshnikov assumed the directorship of the company in 1980, Ms. Tharp followed up with ''The Little Ballet,'' ''Sinatra Suite,'' ''Bach Partita'' and the public-TV special, ''Baryshnikov by Tharp.'' In 1984, Ms. Tharp collaborated with the choreographer Jerome Robbins on ''Brahms/Handel'' for the City Ballet and, the next year, created dances for Mr. Baryshnikov and Gregory Hines in Taylor Hackford's 1985 film ''White Nights.'' Making the Decision To Quit Dancing
Ms. Tharp's own career as a dancer is yet another chapter that the choreographer recently decided to close. Dancing, she says, had simply become too physically taxing as well as a luxury she could ill-afford. ''When I had to confront, 'Hey, wait a minute, you can't do as much you could, you're going to have to stop,' I'd think, 'What am I going to do?' To suddenly pull that rug out from under one's self-definition was very painful.'' Still, she keeps half her living room cleared, ''so I can just futz around in there from time to time.''
Ms. Tharp, whose one-year contract with Ballet Theater leaves her free to explore other pursuits, is now in Paris creating her first piece for the Paris Opera Ballet. This past summer, she enrolled in Columbia University's Film Department; film projects are definitely on her mind, admitted Ms. Tharp, as is the just-completed first draft of her memoirs.
Writing those memoirs was ''critical'' in helping her clarify her change in direction, she said. ''When you sit down and analyze your whole career, it's easier to say, 'This is what I want to get done and I can get it done better that way, even though that way is going to hurt.' Doing this move was very difficult emotionally. My company has been a family.''
Her new relationship with Ballet Theater has clearly enabled Ms. Tharp to get work ''done.'' In the past three months she has created three ballets, the first of which is a large-scale narrative piece to songs by Jerome Kern that she constructed ''as if I were pacing a film.'' Set in the late 1920's on an ocean liner, ''Everlast'' charts the attempts of an financially marooned matron to marry off her whimsical daughter to a boxing champ. Confront the Challenge of Narrative
A leading proponent and creator of abstract dances throughout her career, Ms. Tharp has recently found herself attracted to dramatic dance, admitting that earlier in her career ''storytelling'' was something she would have shunned.
Of course, she has not totally forsaken abstraction and is at work on ''Quartet,'' a rigorously structured ballet for several of A.B.T.'s principal dancers. ''I feel I can handle the architecture of dance as well as anybody,'' she said. ''There will always be movement, structural and counterpoint challenges for me in abstract dance, but now I find that you need a narrative to deal with emotional issues. If you can look at a dancer onstage and say, 'Oh, yeah, this guy has a problem and I know what the problem is about,' then you have a different way of connecting with a lot more people - which I always saw as a positive goal.''
Her ''connection to narrative,'' Ms. Tharp said, owes a good deal to her childhood exposure to the movies while working at her parent's drive-in theater in San Bernardino, Calif., where the young Tharp saw ''six features and 14 shorts every week for 10 years.'' Her decision to enroll in film school grew out of the realization that she needed to learn what she calls ''the nuts and bolts'' of narrative. Noting her dissatisfaction with her own theatrical ventures - which include ''When We Were Very Young,'' a 1979 work with text by Thomas Babe, ''The Catherine Wheel,'' made in 1982 to commissioned music by David Byrne and later adapted for television, and ''Singin' in the Rain'' - she said: ''The problems of narrative have continued to challenge me, so I decided, no point in stopping now, what with a mere three failures to my credit.''
Ms. Tharp concedes that she has traveled a great distance since her avant-garde beginnings, ''when I only wanted to invent my own rules.'' As she explained: ''When I started thinking seriously about learning the rules of narrative, I thought, 'You've learned the rules of dancing from the ballet, what's the matter with learning the laws of theater from the people who know how to do it?' ''
To that end, she studied film editing, screenwriting and directing, read the memoirs of the playwright-producer George Abbott and poured over archival tapes of dramatic ballets by Balanchine and by the late Royal Ballet director Sir Frederick Ashton. When she returned to the studio this past summer, she led a group of Ballet Theater dancers in an acting workshop to expand their dramatic abilities, an experiment she hopes to put into practice at Ballet Theater.
Ms. Tharp has also just put the finishing touches on the burlesque and vaudeville-inspired ''Bum's Rush,'' a work she began last year in her own company and that remains a showcase for the dancers she brought with her to A.B.T. She admitted that its dramatic demands - which call on the dancers to scream, laugh uproariously and tell jokes while dancing - may prove tricky for Ballet Theater's dancers to assimilate.
To the choreographer, ''Bum's Rush'' is about people ''who figure out a way to keep it together when the odds are against them.'' Not surprisingly then, she sees a parallel between its themes and her own situation. ''To survive,'' she mused, ''you've got to keep wheedling your way. You can't just sit there and fight against odds when it's not going to work. You have to turn a corner, dig a hole, go through a tunnel - and find a way to keep moving.'' TWYLA ALUMNI
Former Tharp dancers have moved in several directions. Veteran John Carrafa, who left the company a year before it was disbanded, created the choreography for two film musicals, both to be released this spring: ''Sing,'' starring Patti LaBelle, and ''Rooftops,'' directed by Robert Wise, who also directed the screen version of ''West Side Story.'' Mr. Carrafa has also been commissioned to do a ballet for the BalletMet of Columbus, Ohio.
Other dancers who left the Tharp troupe more than a year ago include Michael Schumacher, now a dancer with the Frankfurt Ballet, headed by William Forsythe; Catherine Oppenheimer, who appears as a dancer in ''Sing'' and is studying acting, and William Whitener, who assisted Jerome Robbins in researching and reconstructing the dances for ''Jerome Robbins's Broadway'' and is currently coordinating the dance department at Concord Academy in Concord, Mass., and working on a new ballet for the Princeton Ballet.
Sara Rudner, who joined the company at its inception, is teaching dance in New York City, and Keith Young is choreographing music videos.
Since leaving the Tharp company in 1985, Shelley Freydont has been dancing with American Ballroom Theater and teaching ballroom dancing; Amy Spencer has appeared in several of the director-choreographer Martha Clarke's productions; Mary Ann Kellogg has worked as a rehearsal director for Ms. Clarke, and Barbara Hoon has been cast as a dancer in ''Jerome Robbins's Broadway.''