Ann-Marie MacDonald was just a kid when she was first told to "write what you know." She was crestfallen by her teacher's instruction, thinking it meant that her stories must be confined to her concrete experience, her boring old life. "I thought, I want to write from my imagination, my ‘what if,'" she says, her hands in the air and her eyes sparkling. As the decades passed and Ann-Marie became a storyteller of many kinds—author, playwright, actor and television host—she realized experience and imagination weren't separate entities. "There is a marvellous, fantastical jungle that grows up from my experience," she says. "That's called the imagination."

Looking back at Ann-Marie's novels to date, one can trace the progression from imaginary worlds to beautifully profound stories inspired by her boring old life. Her successful 1996 breakout novel, Fall on Your Knees, was an epic family saga derived from her Lebanese and Cape Breton background. Years later, in 2003, she followed up with The Way the Crow Flies, a story in which the main character lives on the same air force base as she did in childhood, in the shadow of the famous Steven Truscott case.

With the September release of her third novel, Adult Onset (Knopf Canada, $32), Ann-Marie faces her past in the most concrete and penetrating way yet: She fictionalizes her experience of estrangement from her parents for being a lesbian. Opening the book with an email she received from her father, Ann-Marie—along with her protagonist, writer Mary Rose MacKinnon—is forced to confront the pain she felt when her parents refused to accept her for who she was.

In some ways, Ann-Marie thought it would be an easy book to write. Unlike her research-intensive previous novel, which required digging into a high-profile murder case, this work of fiction is about familiar subject matter: raising two kids, being a writer (like Ann-Marie, Mary Rose is constantly asked when her third book will be done) and dealing with rejection from her parents. But turning something so personal into fiction ended up being one of the hardest things she has ever done.

Now Ann-Marie's often dramatic voice softens as she reflects on it. "This has been the greatest work of fiction in my life, because I've had to deal so finely and so delicately with what I've drawn on," she says. You can't help but appreciate all the careful work that went into this novel and, most notably, into creating its protagonist. Lovable yet hopelessly flawed enough to be utterly human, Mary Rose is a character who is uncertain. A character who questions her sanity, Googles her symptoms and dwells on the past. A character you can't help but see yourself in.

And as a mother, Mary Rose is refreshingly real. Unlike the idealized, ever-patient moms commonly portrayed in fiction, she experiences moments of hair-trigger rage—and it terrifies her. "The idea that a mother is supposed to be flooded with her own oxytocin and just in love with love—it's not always like that," says Ann-Marie, who deliberately weaves those moments of chaos that come with having kids into the story line. At one point in the book, the analogy-loving author sums up everyday motherhood: "Child rearing resembles war: long stretches of boredom punctuated by all hell breaking loose."

Now a mother of two daughters, ages nine and 11, Ann-Marie says motherhood has made her a better person, one who plays hockey with other moms and knows her neighbours. But it has also dredged up buried anger from her past: While she now has a strong relationship with her parents, who eventually came around, she was harbouring residual pain somewhere in her psyche. "I thought all of that was dealt with and done, but children force you to confront yourself in a way that no one else can," she says. "If you've experienced that kind of exile and you haven't completely processed it, you pass it on to the next generation. And you won't even know that you're doing it."

In Adult Onset, that pain is everywhere. Haunting memories are nestled in with the minutiae of life. Mary Rose replays some of those memories, meditating on them, turning them around and examining them from different angles. You can't help but think that, in some way, Ann-Marie was doing the same in writing the book. But she teaches us that memory is far from perfect.

As Mary Rose seeks to illuminate her past in search of answers, all she finds are more questions. "When you have uncertainty about an aspect of your past that has made you who you are today, it can really bother you in the back of your mind," says Ann-Marie, who seems to have come to terms with the uncertainty in her own life. Though it can drive you crazy, it's also the key to endless possibility, she says. "You'll never get the answer, but if you're lucky, you'll get new questions." 

If you're looking for more great books, here are the 5 best fall reads for moms.

This story was originally titled "Getting Real" in the October 2014 issue. Subscribe to Canadian Living today and never miss an issue!