First came the blog-to-book; now, the YouTube video–to-book. Several online celebrities—or, more likely, their caretakers—are trying to leverage Internet popularity to capture young readers. But will Web fame translate to viral book sales?

A young polar bear in the Rotterdam Zoo recently made quite a splash online when he was videotaped tossing rocks at his glass enclosure. Vicks the Polar Bear Cub by Mack chronicles the cub’s life story; children can follow Vicks taking his first steps, catching fish, and learning to swim, through photographs and accompanying text. (Clavis)

British cousins Sophia Grace Brownlee and Rosie McClelland went from the YouTube screen to the Ellen studio stage seemingly overnight. Now, at ages eight and five, respectively, they star in Tea Time with Sophia Grace and Rosie, illustrated by Shelagh McNicholas. In the book, the cousins choose a theme for their tea party, create invitations, decorate their bedroom, and try on outfits. (Scholastic/Orchard)

The residents of Aviarios Sloth Sanctuary in Costa Rica are poised (on three toes) to enter the world of publishing, in A Little Book of Sloth by Lucy Cooke, a National Geographic zoologist and filmmaker. With their climbing, eating, sleeping, hugging, washing, and snuggling—all done verrry slowly—the lethargic leaf-eaters have entertained millions on video-sharing sites. Cooke’s photo-packed volume invites parents and children to see the sanctuary’s efforts to rescue and rehabilitate these creatures—and gaze at the sloths’ sleepy, inviting facial expressions. (S&S/McElderry)