A book without a cover, almost always a mass market edition. Because it is not cost-effective to return or remainder mass market editions, their covers are torn off by the retailer and shipped back to the publisher as proof the books have been destroyed. The retailer then destroys the books. This is the reason for the "If you purchased this book without a cover..." disclaimer on the first pages of many mass market editions. Strippable books are marked with an "S" inside a triangle, often on the inside of the front cover.