THE FLAVOUR of the eigtheenth edition of the Dewey Decimal Classification can perhaps best be appreciated by a quotation from its preface: ‘The Decimal Classification Editorial Policy Committee hopes that this Edition 18 will prove to be a happy combination of the high principles of Edition 17 and the ease of use of Edition 16.’ This reference to ‘high’ principles might raise the eyebrows of the founder of the scheme. Ease of use he would heartily endorse. The high principles referred to are the concepts of subject integrity and the hierarchical nature of the schedules and the notation. These particular high principles were suddenly discovered by the editors of Edition 17, though they had been implicit in all classification schemes since 1876, with the exception of J. D. Brown's Subject Classification. In this country we would prefer to call subject integrity ‘classification by discipline’. In spite of this emphasis on classification by discipline, the conflict between this concept and the opposing one of ‘facet analysis’ which was present in previous editions is still present in Edition 18. The two processes work in opposite directions and the basic problem is to decide where classification by discipline should cease and facet analysis begin. Derek Austin, in a talk to the Cataloguing and Indexing Group of the Library Association in April 1967, pointed this out. For example, in 630 Agriculture the method of facet analysis is clearly at work. We have the energy facet stated at 631–632 under operations and problems in agriculture. The crop facet follows at 633–635, with the ability to qualify certain crops by operation and problem. This is pure facet analysis. But, as Austin points out, at 658 Management we find classification by discipline in operation: