Our aim here is to present the layers his thought, as we understand them, in a systematic and simpler, but not simplified manner, that is, without losing the integrity of what we see as his intent. Ranganathan was not only concerned with facets. They were one part of his approach to designing and successfully using classification. The reason for presenting Ranganathan's theory in the form of a model is one rooted in activism. The book covers the latest Dewey Decimal Classification, provides practical advice on which schemes will be most suitable for different types of library collection, covers classification of digital resources and explores recent developments in digital resources and tagging and so on. Researchers in the field of library science will get a good foundation in the theory as well a practical help in the application of whatever schemes their libraries use.