We are pleased to announce publication of Differences Between, Changes Within: Guidelines on When to Create a New Record (revised edition, 2007). This revised edition is now available as a free, 38-page download (.pdf) and is no longer available as a print publication.Originally intended to be an appendix to the 2002 AACR2 rule revisions, Differences Between, Changes Within evolved into a stand-alone document that supplements current descriptive cataloging rules by providing information about creating new records or updating existing records.The document helps guide the cataloger in determining whether the item in hand can be cataloged with existing copy or requires a new bibliographic record. General guidelines are followed by specific guidelines for manifestation-level records for single-part monographs, multipart monographs, integrating resources, and serials. The text describes what constitutes a major difference between manifestations, requiring the creation of an original record, as well as detailing major changes within a serial manifestation that would lead to the creation of a new record. In addition, guidance is also provided to identify minor changes that would not require a new bibliographic record, but might necessitate updating an existing record.The new edition of Differences Between, Changes Within reflects changes through the final set of amendments to AACR2, which were issued in 2005. Some guidelines have been changed and some removed. All rule references have been verified and updated wherever necessary.