My Beloved Monster by Caleb Carr review – love letter to an adored companion

She had eyes that were “remarkable for their deep amber colour, as well as for their enormous size and proportion to her head”. Keen to communicate with her in a profound sense, Carr closed his eyes, and “reopened them several times, the slow blink of friendship”. Emboldened that Masha “seemed receptive”, he then did what anyone might in his position: he adopted her – for Masha is a cat – and took her home with him, where they’d spend the next 17 years, hunkered down together, inseparable.

“If you are tempted to use such a phrase as just a cat,” the author warns early in his new memoir, “I can only hope that you read on and discover not only that she ruled her untamed world, but brought life-affirming purpose to my own.” Throughout the 352 pages of My Beloved Monster, Carr, an American crime writer and military historian who died earlier this year from cancer aged 68, sets out what may be the most effusive paean to cat love ever committed to paper.

Carr had a complicated life. As a writer, he came to prominence with his million-selling 1994 crime novel, The Alienist, but the fallout from his unhappy childhood defined him. He’d been raised in New York in the 60s and 70s with “often violent alcoholic” parents. His father, Lucien Carr, was part of the beat crowd and, his son relays, “had a habit of knocking me down flights of stairs”. The reason soon seemed clear: “He was trying to kill me.”

Little wonder, then, that Carr went on to develop a profound mistrust for humanity in general. Throughout his life, he suffered with ill-health. He had peritonitis, extensive scarring across his torso and stomach, and further chronic health problems that, he believed, nixed any potential for lasting romance. He moved to the Misery Mountains in upstate New York, where he lived alone, except for cats. When My Beloved Monster opens, Carr is already pining the loss of one, Suki. Masha, a wild Siberian, is the necessary replacement.

Carr believes himself to be “some crossbreed” between feline and human, and therefore able to communicate with cats. When he adopted Masha, who had long been overlooked at the animal shelter owing to a feral nature that terrified potential candidates and staff alike, “something that sounded suspiciously like yeah! popped out of her mouth”. Within these pages, Masha is not merely beloved pet but partner, confidante, equal. Together, they suffered – his ongoing poor health, her frequent fights with inquisitive dogs and territorial bears – but they brought succour to each other.

When Carr died in May, the Guardian obituary noted that he did not take kindly to negative reviews of his books, particularly if they were by women. With Masha, he finally found a female he could get along with. (Her memoir, had she been able to write it, might have proved even more revealing.)

It’s a cold hard fact that most pet memoirs don’t end well, and My Beloved Monster fulfils that necessary circle-of-life narrative. Carr dealt with it stoically because he believed in life after death, convinced they’d one day be reunited. “Since falling on to this Earth, I have proved as difficult for my fellow human beings as they have often proved for me,” he writes. “But for Masha, no such questions. I was enough.” His final book is certainly testament to that.

• My Beloved Monster: Masha, the Half-Wild Rescue Cat Who Rescued Me by Caleb Carr is published by Allen Lane (£25). To support the Guardian and Observer order your copy at guardianbookshop.com. Delivery charges may apply