Three Levels of Description
The three levels of description are detailed thus:
First Level of Description: For the first level of description the following elements are the minimum. Guidance is to be taken from the General rules 1.IB, 1.IF, 1.2B, 1.3, 1.4D, 1.4F, I.5B, 1.7 and 1.8B for this purpose. Title proper/first statement of responsibility, if different from main entry heading in form or number or if there is no main entry heading. - Edition statement. - Material (or type of publication) specific details. - First publisher, etc., date of publication, etc. - Extent of item.-Note(s). - Standard number.
Second Level of Description: For the second level of description the following is the schematic illustration of the minimum elements: Title proper (general material designation) = parallel title: other title information/first statement of responsibility. - Edition statement/first statement of responsibility relating to the edition. Material (or type of publication) specific details. First place of publication, etc.: first publisher, etc., data of publication, etc. Extent of item: other physical details: dimensions. - (title proper of series/statement of responsibility relating to series, ISSN of series: numbering within the series. Title of sub-series, ISSN* of sub-series; numbering within sub-series). - Note(s). Standard number. (*ISSN =International Standard Serial Number). Let us see what Wynar's book Introduction to Cataloguing and Classification has to say on this level. He says "The third level includes every possible element set out in the rules and is likely to be used only in cataloguing such things .as rare items".
Third Level of Description: In this level of description all elements set out in the rules of AACR-2 which are applicable to the particular item that is being catalogued are to be included.