The author of \"Captain Underpants\" is joining the digital age, and bringing back his million-selling series after a 6-year hiatus. Scholastic Inc. announced Thursday that e-editions of two graphic novels by Dav Pilkey, \"The Adventures of Super Diaper Baby\" and \"Super Diaper Baby 2,\" will come out at the end of January. The releases will include deleted scenes and material about the making of the books, spinoffs of the \"Captain Underpants\" stories. The proliferation of iPads, Nooks, Kindle Fires and other color devices have made publishers and authors increasingly willing to put illustrated works in electronic format. Scholastic also announced that two new \"Captain Underpants\" books are arriving, the first since 2006 and continuing the adventures of schoolmates George Beard and Harold Hutchins and the principal they turn into an underdressed superhero. The titles alone should give kids the giggles: \"Captain Underpants and the Terrifying Return of Tippy Tinkletrousers,\" to be released in August, and \"Captain Underpants and the Revolting Revenge of the Radioactive Robo-Boxers,\" scheduled for January 2013.