Roz Chast sheepishly approaches the front desk of the Hotel Nikko in San Francisco to reveal that she has [wince] locked her card key in the room. I have not met her yet—I am waiting near the desk to catch a glimpse of the New Yorker cartoonist as she emerges from the elevator—but overhearing this makes me smile. It’s classic Chast. If she were to draw the scene, her hair would be frazzled, her eyes crossed, exclamation points and swirls would encircle her head to emphasize her self-deprecation. The real-life Roz really is the sincere, baffled observer she depicts in her cartoons.

After talking with her in a quiet corner of the hotel lobby for almost two hours, even more appealing aspects of her personality were revealed. For one: she changes voices. Many of her impressions sound like enthusiastic salesmen of the 1950s and poke fun at her very challenging upbringing by two older and incredibly quirky parents—the voices are a coping mechanism for Chast, who was an only child. And, unlike some interviewees, who want to portray themselves in their most flattering light, she cusses unapologetically. Not what you’d expect from a contributor to a highbrow literary mag and resident of a staid Connecticut suburb.

All of these traits flow through Chast’s clever hand, resulting in some fourteen books, ranging from compilations of her New Yorker cartoons to several children’s books, one of which is a hilarious romp through the alphabet with Steve Martin. Her latest book, a memoir, Can’t We Talk About Something More Pleasant?, was a finalist for a National Book Award. In it, Chast focuses solely on her parents, a couple who “aside from WWII, work, illness and going to the bathroom did everything together.” Only here her parents—longtime favorite subjects, who have appeared in countless depictions since she published her first cartoon in the New Yorker, in 1978—have the spotlight all to themselves. Chast chronicles their not-too-pleasant journey from the mere inconveniences of old age to their messy and prolonged deaths. Granted, this is an unlikely subject for what are, in essence, cartoons. But it’s exactly that treatment that makes Chast’s graphic chronicle palatable. Death is no laughing matter, yet somehow her illustrations and honest, compassionate, and funny narrative see the reader through.

Chast’s book tours for the memoir have attracted legions of fellow baby boomers who show up ready to unload their own experiences in elder care. The book is practically a cautionary tale for a generation, yet of course applicable to everyone whose parents will eventually die, as parents eventually tend to do. She offers little advice except to face up to what’s...