The high prices of textbooks, which are approaching $1,000 per year for an average student, have those students and their professors crying for mercy. Flat World Knowledge, a new digital-textbook publisher, has the answer to this problem. Starting next year, the publisher will offer online, peer-reviewed, interactive, user-editable textbooks, free of charge. The books will include images, audio, and video and will be structured as "social learning" sites, meaning students can chat and share notes while reading. Instructors who adopt the books can also edit the authors' words without permission. While this model may not appeal to authors who have spent years slaving over their texts, other authors see it as a welcome means for continuous peer review.