Sliding Surrogates (2024) is an experimental bibliography that tracks and documents examples of library catalog records that display the wrong book cover thumbnail images. This phenomenon is not altogether uncommon as library catalogs import cover images in batches from third-party services. When two dissimilar sets of metadata are incidentally linked and merged (a text-based bib record plus a cover thumbnail image), the sliding surrogate such as it is publicizes a work that no author, designer, printer, or publisher imagined. A third transgressive bibliographic object emerges, here reimagined using color transparencies and lenticular prints.