harlotte von Mahlsdorf, née Lothar Berfelde, was a celebrated German transvestite and homosexual who, through a mixture of guile, courage and self-preserving compromise, endured the two cruelest 20th-century regimes in the West.

Her story — Mahlsdorf, who died last year, referred to herself in the feminine — is spectacular. As a 15-year-old, she bludgeoned her Nazi father to death as he slept. In World War II she maintained a secret gay nightclub in Berlin. And after the division of the city placed her in the East, she survived the virulently repressive Communists in spite of their thoroughgoing disdain of homosexuality and gay culture, evidently by informing on many of her closest friends.

A documentary film about Mahlsdorf was made in 1992 (before the betrayals came to light), the same year that the playwright Doug Wright traveled to Berlin and encountered her at the private museum she organized and ran for decades.

Thus began a peculiar relationship between playwright and subject that has resulted in the provocatively titled "I Am My Own Wife," a one-actor play that opened yesterday at Playwrights Horizons, with Jefferson Mays delivering an extraordinary performance.

Directed by Moisés Kaufman with heartbeat precision, the play is, on the one hand, a fascinating and beautifully written character study of Mahlsdorf, whom Mr. Wright, who is gay, initially viewed as a hero and an inspiration but whose story turns out to be much more complicated than a mere profile in courage.

On the other hand, it is a kind of confession by Mr. Wright. He had kept up a correspondence with Mahlsdorf and returned to interview her many times, only to end up terribly disappointed by some of what was revealed about her. It appears that these revelations caused Mr. Wright to make himself a character in his own play, which turns into a story of their relationship and their mutual need to believe in a somewhat fictionalized version of Mahlsdorf's life.

"So, at the end of the day, what have I got?" the character called Doug asks, pointing up what is really the only soft spot in an otherwise compelling evening. Mahlsdorf's story is so absorbing, eventful and unusual that she herself is overwhelmingly more interesting than Mr. Wright's struggle to make sense of her. You are always hungrier for more about Mahlsdorf than about Mr. Wright's relationship with her.

Yes, his expressions of frustration, his conversations with his friend John and the increasingly intrusive presence of the mass media in Mahlsdorf's life (all depicted deftly by Mr. Mays) are often amusing and diverting. And yes, you can't help sympathizing with the predicament of a writer who is entranced by his subject and then suddenly faces disillusionment.

But it nonetheless feels like something of an abdication of a playwright's responsibility to say, as Mr. Wright does, that he doesn't know how to tell the subject's story, so he'll tell his own. Mr. Wright acknowledges as much with the play's subtitle: "Studies for a Play About Charlotte von Mahlsdorf."

This is an important caveat, but it isfar from damning; if "I Am My Own Wife" is not quite as terrific as it might be, that is because it is terrific enough to raise the highest expectations. From the moment Mr. Mays enters in a simple black dress, sensible shoes and a string of pearls, carrying a Victrola and moving with the calibrated meticulousness of an elderly woman, you are riveted by his commitment to the character's self-knowledge and proud eccentricity. Mr. Mays, who plays some 40 characters, slipping from voice to voice and posture to posture with adroit aplomb, is most vivid in the central role.

As Mahlsdorf, he shows us a unique individual, seemingly harmless and tender, eerily composed, deliciously unapologetic for her unusual persona and fiercely protective of her life's work. Born in 1928, she spent a lifetime accumulating period furnishings from the 1890's in Germany: "petroleum lamps and vases, gramophones, records, matchboxes, telephones, inkwells, polyphons, pictures, credenzas, bureaus and, of course, clocks." And she turned her home into a museum, which the set designer Derek McClane has rendered (and David Lander has lighted) with rich subtlety, presenting burnished antiques rising on shelving behind a mostly bare room that is wallpapered in grandmotherly style.

Mr. Kaufman rightly keeps the atmospheric focus on the obsessive mentality of the collector. This gives the character of Mahlsdorf a principal motivation: she has a kingdom to defend, which, in the second act, she does with increasing desperation as it begins to fragment.

The kingdom, of course, is tiny. And as if to underscore the poignancy of this, Mr. Wright has written a museum tour scene in which Mahlsdorf sits at a table and shows off dollhouse miniatures of her artifacts; it's beautifully staged by Mr. Kaufman and performed with great delicacy and gentility by Mr. Mays. This idea of a tiny, personal kingdom keeps the play a properly humble tragedy rather than a grand one; it isn't "King Lear," after all. But it also gives Mahlsdorf's story a grandeur that the play could justify but finally does not.

I AM MY OWN WIFE
Studies for a Play About Charlotte von Mahlsdorf

By Doug Wright; directed by Moisés Kaufman; sets by Derek McLane; costumes by Janice Pytel; lighting by David Lander; sound by Andre J. Pluess and Ben Sussman; production manager, Christopher Boll; production stage manager, Andrea Testani. Presented by Playwrights Horizons, Tim Sanford, artistic director; Leslie Marcus, managing director; William Russo, general manager. At 416 West 42nd Street, Clinton.

WITH: Jefferson Mays (Charlotte von Mahlsdorf, et al).