The adult coloring book craze that started at the beginning of 2015 shows no sign of slowing down. Lost Ocean, Johanna Basford’s newest book (and her first published by Penguin), sold more than 55,000 copies in the first week after its October 27 release, according to Nielsen BookScan. Her first two books were published by Laurence King: Secret Garden and Enchanted Forest have sold more than 453,000 copies and 350,000 copies, respectively, so far this year.

Since adult coloring books don’t have their own BISAC code, they appear in different categories in BookScan, but most titles are grouped under art, and coloring books dominate that list (Basford’s books appear on the juvenile nonfiction list). A list of some of the biggest sellers to date shows that 10 of the most popular books have combined to sell about 1.5 million copies at outlets that report to BookScan, which captures about 80% of print book sales. And many publishers note that they have done very well in nontraditional outlets that do not report to BookScan.

It is hard to find a publisher that hasn’t entered the adult coloring book market. The independent publisher the Experiment, for instance, has more than 280,000 copies in print of The Mindfulness Coloring Book, which was released in June, and more than 85,000 copies in print of the second volume, which was published on October 20. Familius Publishing just signed a deal with Pamela Smart, an artist in Boise, Idaho, to release Color Me Your Way, her internationally bestselling series of adult coloring books, to the U.S. trade. The four titles had previously been available only in one mass merchandiser, where they are likely to sell more than one million copies before the end of this year.

Indeed, coloring books have sold very well across North America. Heather Reisman, CEO of Canada’s Indigo Books & Music, in discussing results for the second quarter (which ended September 26), credited adult coloring books with significantly lifting sales throughout the chain. To give coloring books another boost, Barnes & Noble organized the Barnes & Noble All-American Art Unwind on November 14 at its stores nationwide. The focal point of the event was an activity in which customers could take part in a nationwide project by coloring a piece of art designed by artist Millie Marotta, creator of the Animal Kingdom and Tropical World coloring books—which are published by B&N subsidiary Sterling Publishing, and which have sold a total of over 160,000 copies this year at stores that report to BookScan.

The coloring book phenomenon is also prompting publishers to look for related niches. Fox Chapel has created a book of stickers that can be colored and then pasted anywhere. In early 2016, Little, Brown will introduce four connect-the-dots books for adults.

A final sign of the continuing interest in the category is the response to PW’s call for information for this feature: more than 150 titles were submitted, and we’ve highlighted some here.

Some Bestselling Adult Coloring Books, 2015 to Date