Though many publishers, booksellers, and printers benefited from the explosion of adult coloring book sales in 2015, perhaps no company gained more than Laurence King Publishing, the original publisher of Johanna Basford’s coloring books. The U.K.-based publisher enjoyed more than a 300% increase in revenue last year over 2014, company founder Laurence King said in an interview at PW’s office last month. The increase was led by sales of Basford’s first two titles, Secret Garden and Enchanted Forest, which sold about 15 million copies worldwide through 2015.

LKP published Secret Garden in 2013 after the publisher’s editorial director, Jo Lightfoot, noticed her work in the graphic arts magazine Creative Review and thought to herself, “This would make a nice coloring book.” LKP’s interest in Basford stemmed from its history of publishing what King called “visually exciting” books.