Some prices are quoted from antique books worth £40,000 from a world-famous library in central London to a mere pound or two for poorly maintained books and rip-offs. When determining a rare book's value, condition is everything. If you need to become familiar with book condition grading terms, you might want to browse our glossary. The grading terms that we use here are pretty standard. Keep in mind when grading your books, that condition is extremely important in the value of a rare book. Don't throw those torn dust jackets away! Even if it might be somewhat unsightly and torn, your book is worth more with the dust jacket than without.