What do you do with an outdated book? If you operate a library, you try to sell it. And if that doesn't work, you throw it away. And this dumpster outside the St. Petersburg main library is proof. Since October, the public library has discarded 8,210 books that were judged obsolete or outdated. What's obsolete? Well, a book about Hillsborough County's sewer system, circa 1957, for instance. Mary Brown, St. Petersburg's library director, said sales of outdated books help the city pay for new books. But some books you have to simply toss, she said.