In order to meet these objectives, the rules are based on several basic principles.
Principle 1: First of all, these rules assume that the entities of most interest to users are the work, the creator (whether a person, a corporate body, or a conference), the subject, the genre, and the form. In order to build complex displays and indexes, it is important that each of these entities be given a language-based identifier so that the user can scan through thousands of entities matched on a search and recognize the one he or she is looking for. The language-based identifier must quickly and concisely identify the entity it represents to as many users as possible, including both users familiar with and users unfamiliar with the entity being identified. Otherwise, the catalog will not be an efficient instrument. This entity identifier should be the name by which the entity is commonly known in the language and script of the cultural community of the catalog. This is a departure from Anglo-American practice which hitherto has preferred the name commonly known in the country of origin, resulting in Russian works and corporate bodies being given the name by which they are commonly known in Russia even in American libraries whose users will know those works and corporate bodies only by their English names. With the current plans to create national authority files that link across national boundaries using computer-based identifiers rather than language-based identifiers, it should be possible to let each cultural region choose its own language-based identifiers. Indeed, it might be possible to allow individual users to choose a particular language and script/transliteration scheme for entity identification in any catalog, regardless of the cultural community of the catalog. This first principle is the principle of the name commonly known.
Principle 2: If the name commonly known is shared by more than one entity, it should be made unique by the addition of whatever information is necessary to differentiate each from the other within the cultural community of the catalog. Otherwise, the catalog will not be an efficient instrument; it will confound under one identifier the expressions of more than one work, the works of more than one author, or works on more than one subject. This second principle is the principle of the uniform identifier.
Principle 3: Use the language of the item before you in order to describe it. Begin with what the item being cataloged says and correct it only when it is known to be ambiguous or erroneous. Remember that not all users will know about error, so correction must be done in such a way that the item remains recognizable to the users unaware of the error. The identifying information on the item being cataloged provides a communication link between the catalog user and the cataloger. The fundamental assumption is that a majority of people who compose citations will do so using the identification information given in the item being cited. The user who comes to the catalog with a citation will be more likely to match a catalog record if the catalog record also uses the identification information given in the item as is. Additionally, it will not be possible in all cases for a cataloger to be able to resolve ambiguity in statements on the item being cataloged. In such cases, it is better to simply quote the item than to make assertions based on incomplete information that may eventually turn out to be false or misleading when all of the facts have been determined. Now that Unicode is being more widely adopted, it is time for us to try to use the identification information given in the item being cataloged even when the script that appears on the item being cataloged is not the script of the catalog. This third principle is the transcription principle.