If a book’s dedication is the opportunity to blow someone a kiss, a book’s acknowledgment feels more like the sort of welcoming hug one might give someone they care about after a long journey. There’s a distinction between the two. It comes down to breadth. Let's break down how to write book acknowledgments.
How to Write Book Acknowledgments
Let’s take Gish Jen’s The Resisters (far and away the only salvageable part of my 2020 quarantine experience). She dedicates the novel:
For all the Eleanors I know
Now that’s some dedication.
Her acknowledgment begins with: “Deepest thanks to my many patient, generous, and helpful readers …” She goes onto list a slew of them before thanking a sizable list of dedicated people, with Knopf, who published her book. Following this, she thanks her family. 
To be clear, every sentence in The Resisters is perfect. It’s no wonder what she bids her son and daughter in her acknowledgment:
“You two are a mother’s dream—a field on a summer’s day, with the bases loaded and the game far from lost.”
Now that’s how to write a book acknowledgment.
That’s a moment of appreciation and salutation, of acknowledging how someone served, even from the bench.
I’m guessing no one buys or reads a book for the acknowledgments, but the people who matter to you (the author) do. It’s your one publishable chance to give props to those who contributed to the general, overall effort it takes to write and publish books, so my advice to you, dear author, is to imagine you’re up for a Grammy or an Oscar.
If you really had time to think about it, what would you say in your acceptance speech?
Some you’ll mention when writing book acknowledgments will be obvious. Your beta readers. Your editor (always your editor). Add to this anyone who pointed or realigned your research in a solid direction. That “special collections” librarian, whose passion informed you, and anyone else who nudged your exploratory efforts. Maybe even your friend’s husband, a detective, who helped you learn how to interrogate a murder suspect (I’m speaking from experience). Go ahead and include anyone with whom you’ve spit-balled a plot twist or bounced an idea off. Maybe someone presented a strange detail that helped finesse a sense of setting or shape the characters you created? Include them in your book acknowledgments, too.
Some authors don’t dedicate their books. Stephanie D. Alexander, author of Charleston Green and The Cracked Slipper Series offers this:
"When the time came to dedicate my fourth novel I realized there were too many people in my literary village to choose just one. From my husband, for his endless support, to a nineteenth-century woman whose brave alimony lawsuit inspired a crucial character, each person mentioned in my acknowledgment (admittedly long-winded) made vital contributions to what became a seven-year labor of love. "
When it comes to writing book acknowledgments, don’t miss anyone, especially the ones who matter. There are those who made a difference and those who continue to make a difference. Even if they’re no longer around, every one who helps writers along the way deserves a pat on the back.
