i202 Fall 2010 School of Information, UC Berkeley

The IFLA includes the abstraction hierarchy in its Functional Requirements for Bibliographic Records in order to assist in cataloging entities. The abstraction itself is a way to define and distinguish between different types of entities in a library system.

The largely abbreviated explanation of the hierarchy you find in chapter two 2 was cribbed from here, which is a much longer and more thorough explanation. It is cited as the source in the book, so in the future if you want more info about something you read in the book, you can check out the citations and chase them down. The URL is in the References sections.

Here's the link to Section 3.2: The Entities: http://archive.ifla.org/VII/s13/frbr/frbr_current3.htm#3.2

If you want some more background, scroll up to the top of the page and start reading there.

I am also again pasting here the example we used in the book:

— The WORK is a purely abstract construct. It is the ideal, in almost a Platonic sense, of an artistic or intellectual creation. It has no single material representation. If we think of Macbeth as a work, we mean what you think of in terms of plot, lessons, and meaning when you think of Macbeth.
— The EXPRESSION denotes the multiple artistic realizations of a work and the actual way it is performed. Examples: A high school performance of Macbeth; Kurosawa’s Throne of Blood; and “specific words, sentences, paragraphs” that make up an early edition of Macbeth. 
— The MANIFESTATION is the physical artifact embodying the work, including digital artifacts. Examples: the high school performance on VHS; streaming movie file of Throne of Blood; the Folger’s Library print version of Macbeth.
— The ITEM or COPY is a single document that exemplifies the manifestation. This level of distinction is important if identical manifestations somehow need to be differentiated. Examples: an uncle's copy of the VHS of the high school performance of Macbeth; the stream you receive from Netflix when you watch Throne of Blood online; and a used copy of the Folger’s Library version in a bookstore down the street. (IFLA, 1998 http://archive.ifla.org/VII/s13/frbr/frbr1.htm#3.2)