In a public library, styling a bookshelf is easy: Just fill it with books. At home, a bookcase needs to do a lot more than hold books.

So how do the pros do it?

Start by thinking of your shelves as a kind of three-dimensional wallpaper that adds visual interest to a room. The things you choose to display should express your personality.

“It’s like a little cabinet of curiosities,” said Jeremiah Brent, an interior designer and the newest cast member of Netflix’s “Queer Eye.” Your bookshelves, he added, offer “an opportunity for people to look in and see where you’ve been and where you’re going.”

In the Manhattan home he shares with his husband, Nate Berkus — a much-photographed space featured in Mr. Brent’s new book, “The Space That Keeps You,” and often seen on Instagram, as well — the bookshelves in the den are always changing. But they’re usually filled with stacks of favorite design books, photos of loved ones and pieces of art made by their children, Poppy and Oskar.

“It’s about having fun and playing around with different ways to layer things in and tell your story,” Mr. Brent said. Here’s how he does it.