It gets much much more complicated than that. There are never ending discussions about FRBR: Functional Requirements for Bibliographic Records. https://www.ifla

It gets much much more complicated than that. There are never ending discussions about FRBR: Functional Requirements for Bibliographic Records. https://www.ifla.org/references/best-practice-for-national-bibliographic-agencies-in-a-digital-age/resource-description-and-standards/bibliographic-control/functional-requirements-the-frbr-family-of-models/functional-requirements-for-bibliographic-records-frbr/ https://www.ifla.org/references/best-practice-for-national-b... * Work is defined as the intellectual or artistic content of a distinct creation. It refers to a very abstract idea of a creation e.g. Shakespeare’s Romeo and Juliet and not a specific expression. * Expression is the intellectual or artistic realization of a work. The realization may take the form of text, sound, image, object, movement, etc., or any combination of such forms. * Manifestation is the embodiment of an expression of a work. For example a particular edition of a book or a specific music recording. * Item is a single exemplar of a manifestation. Cataloguing is generally done, based on an item directly available to a cataloguer