From MARC must die!
"Which are the new objectives in this environment and how can we express them. That is what we ought to discuss." - Knut Hegna 
A patron should be able to find an item if: the author is known, OR the title is known, OR the subject is known.
Function of the catalogue The catalogue should be an efficient instrument for ascertaining0 1. whether the library contains a particular book specified by a. its author and title, or b. if the author is not named in the book, its title alone, or c. if author and title are inappropriate or insufficient for identification, a suitable substitute for the title; and 2. a. which works by a particular author and b. which editions of a particular work are in the library
2.1 The Alphabetic Catalogue and its Function § 101 The alphabetic catalogue of a library should, first and foremost, ascertain whether a specific edition of a work is in the collection. Furthermore, to the extent defined by these rules, the catalogue should collocate a) works by a particular author or corporate body b) different editions of a work
The tasks [of bibliographic data] are defined in relation to the elementary uses that are made of the data by the user:
- to find entities that correspond to the user’s stated search criteria (i.e., to locate either a single entity or a set of entities in a file or database as the result of a search using an attribute or relationship of the entity);
- to identify an entity (i.e., to confirm that the entity described corresponds to the entity sought, or to distinguish between two or more entities with similar characteristics);
- to select an entity that is appropriate to the user’s needs (i.e., to choose an entity that meets the user’s requirements with respect to content, physical format, etc., or to reject an entity as being inappropriate to the user’s needs);
- to acquire or obtain access to the entity described (i.e., to acquire an entity through purchase, loan, etc., or to access an entity electronically through an online connection to a remote computer).
What, if any, are the new objectives of library metadata/bibliographic descriptions etc in the current climate?