After six years without appearing in a new adventure, Dav Pilkey’s indomitable Captain Underpants will be back in all his caped, alliterative glory next August. That month, Scholastic will release Captain Underpants and the Terrifying Return of Tippy Tinkletrousers, the superhero’s ninth adventure. Flying onto bookstore shelves not long after that will be Captain Underpants and the Revolting Revenge of the Radioactive Robo-Boxers, the series’s 10th installment, due in January 2013.

And Pilkey will soon make his e-book debut: on January 31, 2012, Scholastic will release e-book editions of The Adventures of Super Diaper Baby and Super Diaper Baby 2: The Invasion of the Potty Snatchers. Each will include bonus material about the making of the books, deleted scenes, and sample sketches.

Launched in 1997, the Captain Underpants series—centering on two mischievous boys who hypnotize their school principal and transform him into a comic book creation—clearly clicked loudly with kids. The series is published in 19 languages, and has more than 50 million books in print in North America alone. The three most recent Captain Underpants installments each debuted at #1 on the New York Times bestseller list, and Dream Works Animation SKG acquired film rights in October.

“Dav Pilkey was really an innovator and ahead of his time in the way he uses illustrations to enhance the story,” says Ellie Berger, president of Scholastic Trade, of the success of the Captain Underpants books. “His humor is unique and has a very wide appeal. It is so kid-friendly, but adults really get it too. And with their mix of text, art, humor, the books engage a broad range of kids, including the most reluctant readers.”

Berger explains that the Captain Underpants series “really broke out in school book fairs” and continues to sell well through that channel and through school book clubs, in addition to retail channels. She expects that Scholastic will eventually publish additional Pilkey titles digitally, noting, “We’re exploring different options to find the right way to expand the series into digital formats while keeping the great value of the printed books.”