Fiction writers are plenty capable of similar bombast. Those outside the publishing business might be impressed that an author knows George Saunders/Toni Morrison/Marilynne Robinson, but those on the inside know that Saunders/Morrison/Robinson was really that person’s creative writing professor.

Image Lindsey Fitzharris Credit... Adrian Teal

The best acknowledgments cop to insecurity explicitly, not by accident. In “The Butchering Art,” which I reviewed only two weeks ago, Lindsey Fitzharris thanks her divorce lawyer for restoring her self-esteem — now there’s something you don’t see every day — and adds that she’s indebted to friends “who reminded me not to let my struggle become my identity.” To one stalwart pal in particular: “You are the hard shell to my taco filling.”

In my imaginary filing system, Fitzharris’s acknowledgments falls into the Heartfelt category. They’re human and humanizing and packed with bonus details. (Turns out she’s part of The Order of the Good Death. Look it up.) Her frank discussion of divorce is a reminder that authors aren’t working on their books in some parallel time and space, but in real time, as real life is happening to them, and sometimes real life is hard.

Image John Green Credit... Marina Waters

Writers are powering their way through illnesses and losses and other unexpected derailments. In “Manhattan Beach,” Jennifer Egan mentions that her brother died last year. (He was young. She wrote through that.) In “Turtles All the Way Down,” John Green thanks two mental health professionals who have made his life “immeasurably better.” It’s the first time many readers will learn of Green’s struggles with an especially intrusive case of obsessive-compulsive disorder.

Read enough acknowledgments, though, and you will also discover how many writers are suffering from common unhappiness, as Freud might say. Rough spells come up so frequently that it raises a pair of questions: Does writing a book itself cause distress? Or are writers already distress-prone?

The answer is likely both. Another persistent theme of acknowledgments, by authors of fiction and nonfiction alike, is that a) most writers are a little bananas and b) books make them even more so. Late-night phone calls come up a lot. So do pep talks. There’s a lot of talk about pride and stubbornness. “I would never want to be married to a writer,” Monica Hesse, the author of “American Fire,” writes as she thanks her husband, “but I’m glad he doesn’t feel the same way.”