Find the Dewey number.

For the solo librarian and the small library that isn’t in OCLC. Look up a Dewey Decimal number by ISBN, by title, or by subject, classifying by analogy when a book has no record of its own. The numbers come from open catalog records — Open Library, the Library of Congress, and other public catalogs — copied, never composed, and yours to verify and adapt to your shelf. For fiction, which usually carries only a FIC label and no number, Dewey Lookup can build a number in the 800s from the author’s literature and period — composed from authority records, and clearly labelled. And when nothing turns up anywhere, it can offer a title-based suggestion — composed, and always labelled as such.