One of the unsung (or at least less-sung) challenges of the first person perspective is getting your narrator to see themselves. In real life, unless it's in an old fashioned personal ad, we don't have much cause to ever describe our appearance. And in fiction, unless its germane to the plot or action, getting a narrator to reveal themselves is difficult to slip in without it seeming shoehorned.
But while a self-description is usually just tossed off, a necessary function of character-driven storytelling, it also hints at a more complicated narrative issue. How aware is the narrator of herself? And how trusted can they be when it comes to their own self-reflection? We can only see the world through the narrator's interpretation of it and the narrator can only see their own face with the help of a reflection.
In The Witch Elm, Tana French's first novel independent of her Dublin Murder Squad series, her narrator Toby Hennessy finds reason to regard and describe himself after surviving a vicious beating by a pair of burglars. The before and after images are important. Once innocuously handsome, the aftermath of violence leaves him dubious-looking. The changes are slight, but they are huge. For the first time in his life, it seems, Toby is aware of how he fits into the world. "The little stuff makes a difference," a detective later explains, painting for Toby how he would look to a jury. "Like the eyelid, you know that thing it does, the... And the limp. The way you slur your words a bit--only when you're under pressure, like, most of the time no one would even notice... But juries don't like that stuff. They think it means that there's something wrong with you."
While Toby is changed physically, the licking also seriously compromises his ticking. His memory and emotion are on the fritz. So much so that his sense of self becomes destabilized. The same way we don't think much about how we'd describe our appearance, we're similarly ill equipped to put a finger on any sort of essence of self. Our idea of who we are doesn't necessarily square with how we actually are. So how much does Toby after the attack resemble Toby before? In his rattled state, our narrator has to look to the people who know him to help fill in the gaps of who and how he is.
Like putting a foot on the floor when you're in bed with the spins, Toby reaches for solid ground by staying at the site of his halcyon on days: Ivy House. The grand old family home now inhabited by his bachelor uncle Hugo, Ivy House is a Proustian portal to Toby's irrefutable past. "All it takes is one whiff of the right smell--jasmine, lapsang souchong, a specific old-fashioned soap that I've never been able to identify--or one sideways shaft of afternoon light at a particular angle, and I'm lost, in thrall all over again." Fully installed to help out his dying uncle, Toby feels as though he's returning to some idea of his former self. Whatever he is is tied up in that property and those memories. His repatriation gets fundamentally complicated, though, when a human skull is discovered in the hole of the old, imposing Wych Elm. The knowability of everyone close to him, including himself, comes under question.
In The Witch Elm, French combines a corking whodunit with a truly exestential whoamI. As a mystery, the novel finds both a first person and a third person narrator in Toby, able to oscillate back and forth between objective and subjective. Everyone is a suspect, even the person telling the story. Murder mysteries have a long and storied tradition of turning people you thought you knew into unrecognizable puzzles, but Tana French has elevated that trope to profound, introspective heights without sacrificing any of the attendant jollies.