If the inscription is personalized, or has historic or literary importance, the copy rises higher still in value. According to Weinstein, a copy of Profiles in Courage that is inscribed to an important historical figure can easily sell for $10,000 to $30,000. An inscription to a private individual that included a sentiment more personal than a simple signature could command a higher price, too. The book that fetched the highest price at a recent Sotheby’s auction of Harry Potter books was a copy of Harry Potter and the Goblet of Fire that sold for $48,000. Normally, it would not go to auction at all because its first edition press run was too big to make it valuable. However, this one contained a handwritten note from Rowling about the Ron Weasley character. Also, this was the dedication copy—the special copy that Rowling gave to her father, to whom she dedicated Goblet of Fire. (Why he chose to sell the unique gift remains a mystery.)

Perhaps the most extreme example of an author’s power to hike the price with a few marks of the pen occurs with J.D. Salinger’s Catcher in the Rye. Weinstein says that unsigned first editions sell for $7,500 to $20,000, but copies signed by the notoriously reclusive author can command prices in the $40,000 to $50,000 range. “I’ve only seen three in 40 years,” Weinstein says, cautioning that autographs of living writers almost never add value because “99 percent of all authors can’t wait to sign their books.”