A reprint of the article "RDA: Why New Cataloging Rules?" by Mark K. Ehlert which appeared in the March 2010 issue of "Minitex/OCLC Mailing" is presented. It discusses the cataloging rules of Resource Description and Access (RDA). The rules of RDA aim to achieve backwards compatibility with the edition of the Anglo-American Cataloguing Rules (AACR2). The applicability of AACR2 principles in the digital world is also discussed.