Most of the DKN modules have been assigned to Topic Categories or "Clusters". Modules that are related by subject, theme or purpose are grouped together to facilitate ease of use and content management. If you were, for example, looking for everything in the DKN about the DAISY 2.02 Validator, you would select "DAISY 2.02 Validator" from the list of topics.
All categories on a specific subject, regardless of knowledge or skill level, are contained within a specific category. Categories are non-sequential, they are subject specific only. As modules about new subject categories are added, new topic categories are added.