Graeme Gibson, Canadian writer and conservationist, has died at the age of 85, his publisher Doubleday Canada confirmed. He was the long-time partner of celebrated writer Margaret Atwood.

Atwood cancelled this week some promotional appearances for her new book The Testaments — a sequel to her dystopian classic The Handmaid's Tale and one of this fall's most anticipated literary releases. The cancellation cited illness in the family.

A cover story in Time magazine earlier this month noted that Gibson was "living with dementia," and that Atwood juggled caring for him while working on her new novel.

Gibson was born in London, Ont., in 1934 and educated at the University of Western Ontario.

He published his first novel, Five Legs, in 1969. An experimental novel about two guilt-ridden young men, a professor and his student, the book was critically acclaimed and sold 1,000 copies in its first week.

Gibson wrote the novel after failing his master's degree and moving to supply teach in London, U.K. with his then-wife Shirley Gibson. He sent the first 60 pages to his friend, Eugene Benson, who returned it with 10 pages of critique.

"He said he couldn't figure out why I was doing it. He also said he could only see eight or four sentences that suggested I had any talent whatsoever," said Gibson to Shelagh Rogers in 2011.

"Then he set out to explain what was wrong with it — the lack of energy. He said if it's not important to you, it's not going to be important to anybody else… He was right."

The following decade Gibson published a novel, Communion, and a nonfiction book, Eleven Canadian Novelists Interviewed by Graeme Gibson. The latter book included a conversation with Atwood, his future partner.

"What do you like most about your own writing?" Gibson asked Atwood.

"Doing it," she responded.

Graeme Gibson interviews the acclaimed writer. 14:18

Gibson and Atwood moved to a farm together in Alliston, Ont. in 1973 and then to Toronto in 1980. Atwood once gifted him a T-shirt that read "Every woman writer should be married to Graeme Gibson" — something a journalist once said to her.

Gibson published two more novels: Perpetual Motion in 1982 and Gentleman Death in 1993. He then made the decision to retire from writing novels.

"I think each of my books was trying to come to terms with everything in my life at that particular time," said Gibson in 2010.

"When I finished my fourth novel, Gentleman Death, it became clear to me that I had nothing left to say as a novelist. I had no desire to write for its own sake."

Gibson later realized that the prevailing theme in each of his books was the human connection to the natural world. An ardent conservationist and birder, Gibson published The Bedside Book of Birds, a collection of words and images exploring the connection between humans and birds in literature. He followed it up with The Bedside Book of Beasts.

An advocate of both Canadian writing and the environment, Gibson took on many leadership roles throughout his life. He co-founded the Writers' Trust of Canada and Writers' Union of Canada and served as president of PEN Canada. He has also been a council member of World Wildlife Fund Canada and chairman of the Pelee Island Bird Observatory, which he was instrumental in establishing.

"We all live as if we're immortal. We do a great job of that. We might as well also live as though we can also make a difference," said Gibson to the Nature Trust in 2011.

Margaret Atwood and Graeme Gibson stop on the red carpet at the Scotiabank Giller Bank Prize gala in Toronto on Monday, November 19, 2018. (The Canadian Press, Chris Young)

Gibson became a member of the Order of Canada in 1992. He's received numerous lifetime achievement awards for his writing and advocacy, including the Harbourfront Festival Prize and Toronto Arts Award.

Gibson reflected on his career in a 2011 interview on The Next Chapter.

"Success is always relative," he said. "The only book that sold well for me was the Bedside Book of Birds. They sit there and they chug along and there they are and I'm pleased with them. They don't cause me any trouble."

Graeme Gibson talks to Shelagh Rogers about his life and his career in writing. (This interview originally aired on Sep 26, 2011.) 14:56

"We are devastated by the loss of Graeme, our beloved father, grandfather and spouse, but we are happy that he achieved the kind of swift exit he wanted and avoided the decline into further dementia that he feared. He had a lovely last few weeks and he went out on a high, surrounded by love, friendship and appreciation," Atwood said in a press statement.

"We are grateful for his wise, ethical and committed life."