21-year-old Aaron Swartz is attempting to turn the library world upside down. He is taking on the subscription-based WorldCat, the largest bibliographic database on the planet, by building a free online book catalog that anyone can update. Many academic librarians are wary of Mr. Swartz's project because it will allow nonlibrarians, who may be prone to errors, to catalog books. Some young librarians are rallying around the precocious entrepreneur, because his work may make their collections more visible on the Web. The new catalog project, Open Library, is set to go live in early March with records on 20 million books. The goal is to create a comprehensive Web page about any book ever published. Each page will include not just author, title, and publisher, but also links that direct users to the nearest library with a copy and to related books. Other links will allow users to buy a book online or write a review of it. The pages will be created or updated by anyone, in the style of the online encyclopedia Wikipedia. Some Web pages will also connect to the full text when its copyright has expired. Or users will be able to pay per-page to digitize an unscanned out-of-copyright book at a college library. The project is similar to WorldCat, which is owned by OCLC, a nonprofit group that promotes technology in libraries, but it seeks to be bigger. While WorldCat catalogs records only from libraries that pay to be part of OCLC, the Open Library will include records from anywhere, free of charge. While librarians maintain WorldCat, the public would maintain Open Library. Mr. Swartz also wants to integrate his database with Wikipedia so that a citation of a book on the popular encyclopedia links to the book's page on Open Library. Another idea is to integrate Open Library with LibraryThing, a site that helps people catalog and share their own books. Eventually, Open Library may expand to include journal articles, too. Should all those connections help increase OpenLibrary'sholdings close to the 72 million unique book records in WorldCat, Mr. Swartz's enterprise could upend the way libraries maintain records. It would be an amazing feat, especially since, at the moment, Open Library is struggling to get libraries that rely on OCLC as a broker for interlibrary loans and other services, to contribute. Contracts with OCLC prevent libraries from sharing their catalog information with for-profit institutions. That does not appear to be a problem for Open Library itself, because the group is nonprofit and small libraries who cannot afford subscriptions to WorldCat, are enthusiastic about Open Library. Since there is nothing to stop Google or any other business from using Open Library's records for commercial gain, many librarians at larger institutions are holding back.