Compiled from 52,000 member libraries (all but 9,134 are North American) the Online Computer Library Center presents its list of the top 1000 library holdings:

we made a master list of all the items held by libraries around the globe. We tweaked it to bring together different printings and editions and translations, and then we counted the number of libraries that own each title. We ranked the titles in descending order by the number of items held by libraries. Then we provided some additional categories to create sublists of fiction, drama, children’s works, and so forth.