Over the next several decades, libraries will face the potential loss of all the e-journals, ebooks, electronic theses, local digital collections, and other "e-stuff" curated for the public good. A solution to this problem is LOCKSS ("Lots of Copies Keep Stuff Safe"), a free, open-source digital-preservation software from Stanford University that preserves digital content in a library-to-library network, just as multiple libraries keep copies of the same book. LOCKSS got its name from its core preservation strategy: LOCKSS boxes--computers running LOCKSS software--share content with one another, ensuring that digital content is not simply backed up to one or two locations but is replicated across a network. While the software is free, membership in the LOCKSS Alliance is necessary for access to e-journals and certain features. (Annual fees for academic institutions range from $1000 to $11,000.) This article describes LOCKSS' installation, maintenance, and format migration. This article also cites the differences between LOCKSS and its competitor, Portico. (Contains 9 resources.)