After four successful decades as an actress, including a costarring role in the current hit TV series Orange Is the New Black, Kate Mulgrew is about to release her first book, Born with Teeth: A Memoir (Little, Brown, April), with uncharacteristic fear.

“Whereas one could say that acting is revelatory, I don’t think it is,” Mulgrew says, as we talk in her Los Angeles hotel suite. “I think you hide when you act. You reveal the character, but you hide yourself. So to come forward in this way, as a writer, has meant an existential shift.”

In Born with Teeth, Mulgrew’s assured writing bolsters her revelation of long-hidden secrets. Describing her childhood at Derby Range, an idyllic family home sitting on 50 acres of land in Dubuque, Iowa, Mulgrew shares family tragedies, the drama in her romantic life, and her determination to be a respected actress—all with a clear memory and eye for detail.

Mulgrew grew up in a large Irish Catholic family with an eccentric artist mother, who called her Kitten, and a businessman father, who was “a very gallant Irishman, very handsome, always with the scotch on the rocks, the cigarette, and the women.” Together they created an environment for Mulgrew and her seven siblings in which the children learned to be independent.

Mulgrew really was born with teeth, two upper and two lower; this medical anomaly occurs only in one of several thousand infants, and in her case it portended her unusual future and a favored place in the family.

“My mother did say, and often out loud to my siblings, ‘Kitty’s my favorite, but I like you, too.’ And then there would be great laughs, but it wasn’t really funny,” Mulgrew says. “There was resentment from my siblings, but they love me, so they have a hard time figuring it all out.”

As a teenager Mulgrew’s dream was to be a poet, but that changed quickly after her mother attended Mulgrew’s first poetry reading. “She said, ‘You can either be a mediocre poet or a great actress,’ and what she meant was, ‘I choose this for you: I think you should go into the theater and you should start now. You will be the one to carry it for me, Kitten, the thing I couldn’t do for myself because I’ve been burdened by all you little irritating kids.’”

When Mulgrew was four years old, her baby sister Maggie died not long after being in Mulgrew’s care for a few hours. The cause of death was most likely sudden infant death syndrome, but to this day she hasn’t forgiven herself.

Then, in college, Mulgrew got pregnant and chose to have the baby, a girl, and give her up for adoption. These events are written about unsparingly in Born with Teeth. “I don’t think any of these things are ever forgiven,” she says. “My book is about regret, and you know, I stand by my regrets. I don’t play that game a lot of people do—‘I have no regrets,’—because I do indeed. That’s the Irish in me. I’m not interested in changing it, not if it can lead me to this kind of self-examination.”

Fans of Mulgrew’s acting have much to look forward to in Born with Teeth. There are discussions of her career highlights: her breakout role in the 1970s soap opera Ryan’s Hope; her theater performances on stages in Seattle, New York, and Los Angeles; costarring with Richard Burton in the film Love Spell; and the smash TV hit Star Trek: Voyager, in which Mulgrew starred as Capt. Kathryn Janeway for seven years. Her current role as Galina “Red” Reznikov in Netflix’s Orange is the New Black, the third season of which will air this April, served, in a way, as the genesis of her memoir.

Describing the character—an inmate in a women’s prison who worked in the prison kitchen and has a strong personality—Mulgrew, 59, unconsciously slips into Red’s Russian accent: “She’s a survivor, and there’s a private place, too, that she keeps to herself.”

“That’s my kitchen,” Mulgrew says. “The kitchen is life. I feed them. There’s something excellent about it, and I need to do that in order to survive. The other women are all in their tribes, but I walk alone.”

Creatively, Red is the most liberating role Mulgrew has ever had. “I let go of my vanity,” she says. “I gained weight. I fell apart, and physically I didn’t care. That’s what I felt it called for, so I stripped it all, and something just flew out of me.” Thus her book was born. “I thought, if you can let go of your vanity, you can let go of your hidden self. And I wanted to be known both as an actress and, with the truest colors, as a writer.”

Mulgrew writes of her marriage to director Robert Egan, the father of her two sons, with a fierceness that is judicious and honest, Mulgrew taking her share of the responsibility for their divorce. Her father recognized her hesitation about the marriage up to the very ceremony. As she writes in Born with Teeth, she and her father stood outside the chapel, Mulgrew in her wedding gown, smoking Pall Malls “like two old Irishmen standing outside of the pub on a wet Saturday evening, legs splayed, arms crossed, the butt held Cagney-style between thumb and forefinger. I rested my head on his shoulder and said, ‘Oh, Dad, I feel so tired.’ Then he turned to me, looked me directly in the eye, and said, ‘You know, Kitten, you don’t have to do this. Just say the word and I’ll go in there and call the whole thing off.’ The wedding march had begun and, taking my father’s arm I said, ‘Fuck it, Daddy, let’s do it.’”

Mulgrew’s mother served as matchmaker for her next significant relationship, with Tim Hagen, which blossomed in Ireland, continued in New York, and ended abruptly when Hagen disappeared without a word for over five years. Later, while visiting Florence with her mother, Mulgrew was seduced by Roberto Meucci, an unpredictable and wealthy young Italian who became obsessed with her. She moved into his palazzo, where he built her a beautiful study.

But the affair was volatile, and, as Mulgrew writes, “Slowly, over weeks, it dawned on me that I was essentially a glorified prisoner, and that the room of my own was merely another enhancement to my gilded cage. Roberto knew what he was doing.” Somehow the affair endured, in Italy and the U.S., and it would have led to a disastrous marriage had Mulgrew’s parents not intervened and stopped it.

Born with Teeth candidly reveals Mulgrew’s emotional challenges, including the price she paid with her sons when they became angry by her all-consuming schedule on Star Trek: Voyager. They felt abandoned by their mother and began acting out their frustrations with a vengeance.

Mulgrew was painfully aware of this predicament and did the best she could to appease the boys, yet she could not help but be flummoxed by Hollywood’s double standards. She writes, “Actresses. What a bunch of saps we are. Madly in love with the child, and with the craft. Trying desperately to forge an alliance between the two and constantly failing. If I were a man, I said to myself, none of this would be in question. My children would respect me, my wife would honor me, and everyone would exalt the work.”

Through it all, Mulgrew felt guilty about giving her daughter up for adoption and carried a profound longing to find her. Mulgrew began searching in earnest in the 1990s. The adoption agency she had used offered no help, so she hired a private detective. In Born with Teeth, the reunion between mother and daughter is described with a tenderness that makes clear the complex mix of emotions that accompanied it. “I have a very strong relationship today with my daughter, due to her goodness and capacity to forgive and to see beyond,” Mulgrew says. “She has forgiven me and she has thanked me for the life I gave her. We’ve sobbed together.”

Readers will hope Mulgrew writes more books. “I very much want to do it, and it would be a marvelous kind of last chapter. I’m always going toward life, never away,” she says boldly. “This is the story of someone who was born with teeth and had to lean into the wind. I don’t go back. Parts of my life are harrowing, and some of them are epic, but then you must move on.”

Wendy Werris is a contributing editor for Publishers Weekly, and a freelance journalist and editor in Los Angeles.