“The fronts of houses lie,” Russell Wangersky writes in the first chapter of Burning Down the House, his memoir of volunteer firefighting in Nova Scotia and Newfoundland, “they’re the faces you’re meant to see.” What you aren’t meant to see is the stuff of backyards, as Wangersky suggests in a telling analogy: he compares firefighting to a train ride he once took.

From that train, the 21-year-old Wangersky observed “the messy parts of people’s lives.” Looking out upon a string of backyards, he was privy to their embarrassingly bared humanity. Later, as a member of the longstanding Wolfville volunteer department in Nova Scotia, and again with the nascent volunteer department of Portugal Cove-St. Phillip’s, Newfoundland, Wangersky observed humanity in similarly unguarded moments.

But the frank nature of Wangersky’s recollections in this, his second book, soon transforms him from an observer into the observed. He describes elements of post-traumatic stress disorder, recurring nightmares, and dissociative episodes that haunt his every hour. The greatest tragedy in Burning Down the House is not the aftermath of any one emergency (and Wangersky does allude to some pretty horrific scenes), but the effect these incidents have had on his mental well-being.

Wangersky describes a “near-pathological” urge to prepare for morbid eventualities. “Sitting at a family dinner,” he writes, “I would try to divine who might suddenly choke.” Watching children at play, he envisions the car that might knock them down, the steps he’ll have to take to administer first aid. Haunted by paranoid fantasy, he becomes unable to function in the world.

The so-called “red devil” –­ a term firefighters sometimes use to describe fire – is not the real subject here. This is a book about the deleterious effects of maintaining professional silence regarding one’s own traumatic experiences. Burning Down the House may be an act of exorcism for its troubled author, but it is also a compellingly candid, incendiary narrative of emotional and mental decline.