A month shy of her 17th birthday, Sonya Lea met the man who would become her husband. Richard was tall, smart and athletic; she was anxious to graduate, to travel, to leave small-town Ontario. They were a match, indie teen movie-style, cut from the same free-spirited cloth. It was not an easy marriage — he struggled with anger, she struggled with alcohol, they struggled with each other — but it was a staggeringly committed one.

And then, after 23 years of marriage, Richard woke up from surgery — a radical procedure to treat a rare kind of cancer — and remembered none of it: not their wedding day, not the births of their children, not work nor sex nor where they lived. "He has gone into surgery as one person and come back another," Lea writes in "Wondering Who You Are," a quietly wrenching memoir that's as much about what makes any of us who we are as it is about Lea's own story. Before surgery, he was sick, but he was Richard. After surgery, he's "a shell."

In the ICU, still largely unable to communicate, Richard writes the same question "over and over in a slanted, strange scrawl: Who is here?" That's Lea's question, too, though for her, it's existential, not logistical — who is this man who is and is not the Richard she knew? The quest for an answer, for understanding, forms the backbone of the book: What is identity without memory?

Moving between their current life — the hospital; the first months at home; the long, slow process of building what's essentially a new marriage — and their past, Lea allows us access to a history the two no longer share. But as she mourns their old relationship, a new marriage begins to take its place. It does not come easily, but it does come, transforming into something kinder and gentler than before.

While our memories define us, Lea discovers those memories are also imperfect creations — an unsettling contradiction. We invent meaning, seek narrative, rewrite the past to match the present. As Richard struggles to recover his history, Lea feeds him stories, realizing in the process, that those memories, "her" memories, are actually collective efforts. We don't own our memories, not the way we think we do.

And perhaps that's not such a bad thing, she suggests, with a kind of peace that's maddening and persuasive. Giving up on the idea of a fixed identity, of accuracy, of an essential "me"-ness, comes with freedom.

"Wondering Who You Are," by Sonya Lea

"Now I wonder who I am," she writes. "I wonder without the desire to know." The loss — in this narrative, at least — has led to something greater.

Rachel Sugar is a writer in New York.