The facet-analytic paradigm is probably the most distinct approach to knowledge organization within Library and Information Science, and in many ways it has dominated what has b termed ‘‘modern classification theory’’. It was mainly developed by S.R. Ranganathan and the British Classification Research Group, but it is mostly based on principles of logical division developed more than two millennia ago. Colon Classification (CC) and Bliss BC2) are among the most important systems developed on this theoretical basis, but ithas also influenced the development of other systems, such as the Dewey Decimal Classification DDC) and is also applied in many websites. It still has a strong position in the fiel and it is the most explicit and ‘‘pure’’ theoretical approach to knowledge organization (KO) but it is not by implication necessarily also the most important one). The strength of this approach is its logical principles and the way it provides structures in knowledge organization systems . Th main weaknesses are (1) its lack of empirical basis and (2) its speculative ordering o knowledge without basis in the development or influence of theories and socio-historical studies. It seems to be based on the problematic assumption that relations between concepts are a priori and not established by the development of models, theories and laws.