WHEN AMAZON launched the Kindle in 2007, book purists bemoaned the imminent demise of print. Yet far from heralding a publishing apocalypse, e-books have been adopted only gradually despite their affordability. Although half of U.S. adults own a tablet or e-reader, e-books make up only an estimated 23% of the $35 billion industry–and Pew Research reports that just 4% of Americans are e-book only.
Sales show digital market share differs greatly by genre, though: While guilty readers of dog-eared Harlequin romances have flocked to the format– Nielsen notes 36% of units sold in that genre in 2014 were e-books–most nonfiction and school textbooks are still purchased in print, per PwC research. The tame-looking Kindle hides many a cheap thrill, too: Digital mysteries accounted for 32% of the genre’s units last year, while e-books made up more than a quarter of young-adult units sold, up from just 8% in 2012, according to Nielsen. Three of the top five Kindle bestsellers of 2014 were YA novels; Gillian Flynn’s Gone Girl and Donna Tartt’s The Goldfinch were the only grownups included. John Green’s teen weepie The Fault in Our Stars was the true standout, however–it was both the top print and e-book seller of 2014.