Knopf Books for Young Readers will release an enhanced e-book version of Christopher Paolini's Inheritance, the fourth and final installment in his Inheritance Cycle, on October 23.

The digital release ($13.99) includes 17 videos of Paolini's behind-the-scenes commentary embedded throughout the text, plus the author's never-before-seen artwork, a letter to fans, and a new scene within the text. Also on October 23, Knopf will release the Inheritance deluxe edition in hardcover ($29.99), the Inheritance trade paperback ($15.99), and the Inheritance Cycle trade paper boxed set ($54.96). These follow the November 8, 2011, publication of Inheritance, which set a record for highest first-day sales in 2011 of any adult or children's title, moving 489,500 copies in print, digital, and audio formats.

In support of the new release, Paolini will make select national appearances. The Inheritance Cycle is available in 125 countries in 49 languages; according to Random House, the books have sold 34 million copies worldwide.