Books Tell You Why discusses the Do's and Don’t's of dust-jackets:
"If you’ve ever purchased a hardcover book, you’re probably familiar with the dust jacket or, depending on which side of the pond you are, the dust-wrapper. Indeed, they’ve been around since the 1820’s! These paper coverings are designed to protect a book’s cloth cover as the book travels from the publisher to your bookshelf. Some readers remove their dust jackets—or even use them as bookmarks! But when it comes to rare books or collectible book, dust jackets should be treated with significant care as they often add significant value to the book."
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>>> Book Collecting Basics: Ditch the Dust Jacket? By Books Tell You Why (March 30, 2011)