of chemical phenomena? (3.9.1) Ayers, Chattaraj, Chermette, De Proft, Fuentealba, Geerlings, Liu, Vela, and Yang : The role of conceptual DFT in this endeavour has been very important: its past and recent accomplishments have been summarized in earlier reviews and a recent "status" paper 475 where also its present status, prospects and issues are scrutinized. The present status can be best understood by considering the aim of conceptual DFT and the philosophy behind its realization.