“I love writing letters,” says 51-year-old actress Mary-Louise Parker, who chose the epistolary format for her first book, Dear Mr. You (Scribner, Nov.). Although it’s tempting to view the letters, which are written to the men in her life, as a memoir, that’s not the case. Some, like the one to her school-age daughter’s future husband, or one to the anonymous oyster picker in the Pacific Northwest who provided her father’s last meal, are clearly people Parker has imagined. Also, as Parker points out, “If this were a memoir, where are the women?” Besides, she adds, “I could never write a memoir. I have too many secrets; I’m too private. I disclose a lot of private things in Dear Mr. You but they’re the ones I wanted to disclose.”

Parker is hidden in plain sight in the coffee shop where we meet near her home in Brooklyn Heights, N.Y. The same could be said for the men in Parker’s life. She changed their names and/or the names of cities or experiences described in the book. She regards the letters as thank-you notes. “I think they’re all about gratitude. I wanted to be positive. I didn’t want the book to be mean,” Parker says.

Although Parker is emphatic, she speaks so softly that even my tape recorder seems to edge closer to her to catch her words. I worry not only about missing something she’s said, but about being interrupted by someone who recognizes Parker from Showtime’s Weeds, for which she earned a Golden Globe and an OFTA Television Award, or The West Wing. She also received a Tony for her role in the stage play Proof and both a Golden Globe and a Primetime Emmy for her performance in the TV miniseries, Angels in America.

Abraham, her accountant is one the few men she writes about whose name is unchanged. Some letters merely identify the man by his job, as in “Dear Doctor,” to the physician who saved her life when she suddenly became very ill during the four-month period in which she wrote Dear Mr. You. As soon as she was well enough to sit up, she resumed writing. Although it made keeping to a tight schedule difficult, on the upside, Parker quips, “it gave me another letter.”

In what Parker describes as the collection’s most “salacious” letter, “Dear Cerberus,” she addresses the lessons learned from falling into bad relationships. Although her publicist requested that I not ask about the identity of specific men in her life, it would seem obvious that one of the monster’s three heads belongs to actor Billy Crudup, who left her for Claire Danes when Parker was seven months pregnant with their son. “ ‘Cerberus’ was an idea,” explains Parker. “I was thinking about dragons, and I read Cerberus. (Cerberus is the multiheaded monstrous dog in Greek Mythology who guards the underworld) That said, I’m not going to tell you who those three people are. There might be four people, and there might be two. I say at the end I could be the monster. We are all dogs.”

Although neighbors, (“Dear Popeye”), and even a co-worker who wears only a loincloth, (“Dear Blue”), also populate the book, Parker acknowledges that in many ways she was really writing about one man, her father, and if he hadn’t died, she probably wouldn’t have written the book. “It’s not about me and dudes,” she says. “I had this archetype, this heroic [and] complicated father, who imprinted so much. I am so like him, and he so understood me and got me. No one will appreciate me like that. The things people don’t like about me are my dad, and the things people like about me are my dad.”

Parker’s father was also a letter writer, and one of his thank-you notes ends the book. In “Dear Mr. You”, she writes: “You are what makes me indomitable and how I know to keep walking when I feel crippled in every conceivable way.” She wrote that essay/invocation, nearly 20 years ago when she was doing publicity for Proof, and Esquire published it. “I had always written, and it was about my dad in the end. And I think they liked it. They kept asking me to write after that and to be on the masthead. It made me super happy. I felt validated. It just felt intractable. No one could take that away from me.” Her literary career with Esquire didn’t deter her from posing nude for the magazine in 2009, which makes her possibly the only author to do both.

Unlike many writers, Parker is relatively thick-skinned when it comes to her prose. It’s as an actress that Parker feels most vulnerable. “As a writer I’m sturdier. If somebody doesn’t like my writing, that’s ok,” Parker says. “Acting, I don’t bank it so much. You can’t take in too much praise or too much criticism. I’m easily thrown, and I always feel I can be thrown.”

While Parker may be best known for her acting, she was a bookish child and surprised her family when she went to drama school. “People always thought I’d be a librarian,” says Parker. “I thought I’d be great librarian, especially for kids books. My mom, the few times anyone’s interviewed her, always says, ‘I always thought she would be a writer.’ ”

Even so Parker has yet to show her family the book. “I’m such a perfectionist,” she says. “I didn’t want anybody to read the galleys. There are typos in it.” She wants them to be able to hold the hardcover and see her father’s favorite food on the cover, which has a Valentine quality to it.

Parker laments her lack of a degree from Harvard or Iowa. But books and literature have always been part of her life, particularly poetry. She lists Mark Strand (her “favorite poet”) alongside people in the theater world, like Mike Nichols, in her acknowledgments. “Because I mostly read poetry, and I mostly like poetry, I like things succinct like that. The best poems have a glorious lack of resolution, but you still feel like you’ve landed somewhere.” She gets increasingly animated as she talks about some of the poets she enjoys, including Kevin Young, Bob Hicok, Jorie Graham, Yusef Komunyakaa, and Caroline Hagood. She wrote about Sharon Olds for Riveter magazine and stenciled a line from Stanley Kunitz on the wall of her house.

Before she began writing Dear Mr. You, Parker worked on short stories. Kate Atkinson is among the fiction writers she admires. “I just read Life After Life. How the hell did she do that?” Parker asks. “I would love to be able to do that. I try not to look at the big picture. I find it gets me more confused; it’s actually not healthy for me. [I] stay on the color by number: Stay on carnation; stay on sunflower. One color at a time.”

Parker is modest about her writing talent. When word got out that she was working on a book, several agents reached out to her and she reached out to others. She chose Eric Simonoff at William Morrow Entertainment, because after reading “Dear Abraham,” he got what she was trying to do. “It’s because of him that I have the book,” says Parker, who had no intention of writing a celebrity autobiography. He believed in her work so much that he submitted the manuscript for Dear Mr. You to publishers blind, without her name on the manuscript. “I wanted editors to engage with the remarkable voice on the page and not mistake the work as a ‘celebrity memoir’ which it clearly is not,” he wrote in an e-mail.

Early readers, who pushed the book onto the November Indie Next list, understood that Parker was writing something more in the tradition of other actor/writers like Jesse Eisenberg or B.J. Novak. “Get ready to laugh, cry, gasp, squirm and relish the candid and endearing writing of Mary-Louise Parker. I am a huge fan of her as an actor and now her brilliant writing abilities are shining just as bright,” wrote Jesica Sweedler DeHart at BookPeople bookstore in Moscow, Idaho.

As to what’s next, Parker says that she has some ideas, but she’s not ready to talk about them yet. “I need another TV role or to sell a kidney,” she jokes. Her film Chronically Manhattan, due out in 2016, with Ashley Benson and Josh Peck is in post-production, and she’s been rumored as a possible star for Showtime’s series based on Mary Karr’s memoirs. Karr blurbed Parker’s book as “a funny, gut-wrenching mediation on her encounters with the masculine.”

On our way out of the shop, we find two pennies on the sidewalk. We pick them up, then toss them and leave them to bring the next person who finds them good luck.