In the Paper are treated the Principles and the Implementation of the Cataloguization and Classification in USA, with a special overview on modern streams. The main goal of the organization of Library Holdings is the satisfaction of different User’s needs for Information. The organization of Knowledge in the Libraries implies the organization of several different types of information and media. In the Paper are described the Anglo-American Rules for Cataloguization and MARC, as standards for the alphabetical Cataloguization. As well the influence of the cooperative cataloguization and the usage of computer technology within the development of these Standards. One can find also a brief description of Dewey Decimal Classification (DDC) and the Classification of the Congress Library in Washington D.C, as the two dominating classificational Systems. Followed by the description of the controled dictionnaries, with special overview on Subject Heading of the Congress Library. The Paper treats also the Problem of Information on the Internet, as well proliferation of the Material in electronic format, which requires the incorporation in traditional library Catalogues.