Last year, a romance publisher took an expensive gamble on the latest novel by bestselling Colorado author Rebecca Yarros.

To help the novel, “Fourth Wing,” stand out in the crowded fantasy-romance genre, the publisher, Entangled, invested in a limited deluxe edition with a bold metallic cover and black sprayed edges featuring dragons.

It worked: All 115,000 copies of the deluxe edition sold out almost everywhere within a week.

“My only regret is that I printed too few,” said Liz Pelletier, Entangled’s publisher.

When the next novel in the series, “Iron Flame,” came out, Entangled was prepared, and printed 1 million copies of the deluxe edition. Once again, they quickly sold out.

For the third book in the series, “Onyx Storm,” which comes out in January, Entangled is printing 2 million copies of the deluxe edition, which has stenciled artwork and black and silver edges adorned with flying gold-and-black dragons, along with a smaller print run of 500,000 standard copies. More than 1 million “Onyx Storm” deluxe editions have already sold. After realizing there was an enormous appetite for special editions, Entangled has started giving the deluxe, sprayed-edge treatment to most of its books, Pelletier said.

“Now, to not spray-paint the edges would send the wrong kind of signal, that a book is not worth collecting,” she said.

After gaining popularity with romance and fantasy readers, heavily adorned editions have spread throughout the publishing industry. Publishers are investing in colorful patterned edges, metallic foil covers, reversible jackets, elaborate artwork on the endpapers, ribbon bookmarks and bonus content.

Deluxe editions have also proliferated because of TikTok, which has reshaped book publishing and marketing strategies. BookTok influencers can send a book skyrocketing up the bestseller list, and elaborately designed hardcovers lend themselves to organic viral marketing campaigns, since readers love to flaunt them to their followers.

“People are really connecting with books as art and as objects that reflect who they are as a person,” said Shannon DeVito, head of books at Barnes & Noble. “Books are the ultimate accessory.”

The growing number of deluxe editions also reveals how fan culture has changed the book business, as publishers increasingly cater to readers’ appetites by distributing more of the same — in some cases, the exact same book with a new cover.

“When they love a book, they want it in all these iterations,” said Erica Sussman, a vice president and publisher at HarperCollins Children’s Books. “Maybe you have the regular edition as the one you page through and highlight passages in, and then you have the deluxe edition to show off on your bookshelf.”

Publishers have found that fancy new packaging can extend the life cycle of a bestseller. Fans will often buy a beloved book again in a bedazzled new package, and the spike in sales can get the title back on the bestseller list, which in turn draws in new readers.

This strategy runs counter to the way most publishers have released books for decades — first in hardcover, the most profitable format, then in paperback a year or so later. Atria published deluxe hardcovers of Colleen Hoover’s novels “It Starts With Us” and “It Ends With Us,” which were massive bestsellers in paperback, and is doing the same for Hannah Grace’s “Maple Hills” series, with special hardcover editions following successful paperback runs.

Some popular titles are cycling from hardcover to paperback to deluxe hardcover. When Taylor Jenkins Reid’s novel “The Seven Husbands of Evelyn Hugo” gained a huge audience on TikTok during the COVID-19 pandemic, the book had already been out for several years, so most of the sales were in paperback. Reid’s publisher, Atria, seized the opportunity to sell a new hardcover to her fans with a special edition that came out in the fall, which has bright green edges ornamented with gold wedding rings. It hit the New York Times hardcover bestseller list.

Publishers have started spraying the edges of some paperback editions, giving fans a reason to buy the paperback even if they already have the hardcover.

All the enthusiasm for fancier books has strained printer capacity, since elaborately designed books take one to two weeks longer to produce than regular editions. Much of the printing for special editions is done in China or Italy, where effects can be added more cheaply, but printers in the United States have also amped up production.

Lakeside Book Co., the largest book manufacturer in North America, has invested in special equipment to apply color and designs to page edges. In the past three years, the company has gone from printing tens of thousands of units of special editions a year, to millions of units, a company representative said.

“There’s not enough capacity today in the market to handle the plethora of publishers saying, ‘I want this effect on my book,’” said Dave McCree, CEO of Lakeside.

Publishers concede there are drawbacks to deluxe editions. Since they take longer to produce and cost more — edge printing and other design elements can add up to 30% more to the cost per unit — profit margins get squeezed.

For now, many deluxe hardcovers sell for $30 to $33, roughly the price of a standard hardcover. But for readers in genres like romance, who are accustomed to buying paperbacks, the jump to a special edition can be steep: Ali Hazelwood’s bestselling romance novel, “The Love Hypothesis,” for example, cost $16 when it came out in paperback in 2021; the deluxe hardcover, coming in June, will go for $35.

Some in the industry also caution that sales of special editions don’t typically expand an author’s audience, and mainly draw in existing fans.

“For the most part, you’re appealing to the already converted,” said Jeff Weber, deputy chief revenue officer at Penguin Random House. In consumer surveys, Penguin Random House found that most readers have little interest in deluxe editions, he noted.

Even so, publishers believe that demand for decked-out copies among committed fans will only increase. Some titles are now getting multiple special editions, with the most devout readers buying them all.