Wendy Wasserstein, the Pulitzer-prize-winning playwright of “The Heidi Chronicles” and “The Sisters Rosensweig,” cultivated a bubbly personality that complemented the mordantly funny observations in her plays and essays about professional women coming of age. But as Julie Salamon’s “Wendy and the Lost Boys: The Uncommon Life of Wendy Wasserstein” revealed upon its release last summer, much was hidden behind Wasserstein’s public image.

When Wasserstein died in 2006 from cancer, at the age of 55, she left behind Lucy Jane, then six years old. The child was born prematurely, after Wasserstein spent years trying to conceive through in-vitro fertilization.  She had kept the pregnancy from some of her closest friends, even the many gay men with whom she had forged a special intimacy. Speculation about the father circulated through the theater world. Possible candidates included a Who’s Who of gay artists: director Gerald Gutierrez, producer Andre Bishop, costume designer William Ivey Long , director Nick Hytner, and playwrights Terrence McNally,  Christopher Durang,  Paul Rudnick, and Peter Parnell. The rumors continued when Wasserstein,  in a New Yorker essay, avoided saying who the father had been.

Salamon shows Wasserstein as carefully controlling what she shared not only with the public, but also her relatives (including her brother, the late Wall Street titan Bruce Wasserstein) and most trusted friends. “How could the most public artist in New York keep so much locked up?” Salamon quotes Frank Rich as asking. Even Wasserstein’s fatal illness was kept such a closely-guarded secret that Rich remembers being stunned when director James Lapine, shaken, approached him on a street corner and said, “Wendy’s dying.”

In this interview, Salamon told us that she is “99 percent” certain that Wasserstein, who died five years ago yesterday, used an anonymous donor. But here as well as in her book, the biographer offers a complex portrait of an influential and most uncommon woman. There is talk, meanwhile, that Lincoln Center Theater (which produced many of Wasserstein’s most important works, including her last play, “Third”) will be reviving her Tony-award-winning “The Sisters Rosensweig” next season.

Why did you devote three years of your life to this project?
Wendy was an accomplished person who led a fascinating life, both personally and professionally. It was also a story about a time in theater and time in the country where women were in the midst of a revolution. In “Heidi Chronicles” she captured the zeitgeist of women caught in the dilemma of how to fulfill the demands of a professional life and still have a personal life.

How did she answer that for herself?
Not really satisfactorily. She was struggling to carve out a life that was not very commonplace. In 1970, half the households in America were made up of mom, dad, and kids. Thirty-eight years later, when she gave birth to Lucy Jane, at the age of 48, that percentage had dropped in half.   

Wendy’s sister Sandra Wasserstein, a senior marketing executive, dies at 60.  Her brother Bruce dies at 61.  A sense of doom hangs over the family in your book.  Or do we just think that in retrospect?
A sense of urgency, perhaps. Not just for Wendy but for her siblings. They were moving at a much faster clip than anyone else and for a complicated group of reasons. Their mother, Lola, had been a frustrated artist. Emigrating from Poland at 15, she’d had a difficult life, losing a husband and having five children, including a severely disabled child, when she was quite young.  She had a lot of ambition and drive and she placed it squarely on the shoulders of her children.

Lola is quite an oddball. In your book, Chris Durang recalls meeting her dressed as Patty Hearst, complete with beret and toy gun.
She was very eccentric and very theatrical. But also very driven.

After the death of her first husband, with whom she has two children,  Lola marries his brother Morris. The younger children are never told that the man they think of as their dead uncle is really their father and stepfather.
That was part of where Wendy’s secretiveness comes from. It was that wall of protectiveness that Lola built around herself and around the family. She had lost several family members in the Holocaust. People don’t need to know everything about you. It’s also a very American story. Poor people come to this country, pull themselves up by their bootstraps and become wealthy. The obsession with celebrity, success, and money and being on top was all part of that Baby Boomer generation.

One of the fascinating threads of the book is Wasserstein’s relationship with gay men, “The Lost Boys” of the title —
Not just gay. That also includes Bruce and Abner [the disabled brother who was institutionalized]. Bruce was a billionaire and married four incredibly attractive and intelligent women and had quite accomplished and lovely children. But he was socially awkward and very much disliked in the business world. He was not widely mourned when he died. But his children loved him. There was an awkward moment at his memorial service. His favorite song, “Some Enchanted Evening” was played and flashed on the screen was a picture of Bruce — all alone.

In the book, Wendy and Terrence McNally, an out gay man, have a physical relationship and talk about having a child and getting married. What was that about?  
Terrence had quite a wild romantic life as a gay man,  but he was approaching fifty and it was a confusing time for him. He’d lost a very close person to him to AIDS and he thought that maybe he’d pursue the path of marriage and family. It was probably not a well-thought-out idea. But the definition of relationships was very fluid in the ‘90s.  It was Wendy’s opportunity to have a warm, brotherly type of love without the competition and familial baggage that she had with Bruce. She was also not comfortable with her body and her gay friends were very forgiving.  I think it probably surprised both of them, neither of them were being realistic. But don’t forget, Wendy was very good at getting what she wanted. She was a very focused and directed person and she wanted to be part of that group.

Any doubt in your mind that her pregnancy was the result of sperm from an anonymous  donor?
I’m 99 percent sure.

And the other 1 percent?
Well, William Ivey Long spent years as a donor, but the pregnancy did not take hold. I’d use his term: “one in a million” chance. Her medical people seem to think it was anonymous. But the other possibility is that it could be someone that I don’t know about. She was very secretive.

What was the source of her secretiveness about her illness?
She didn’t want anybody to feel sorry for her.