Domain engineers describe universes of discourse such as bookkeeping, the financial service industry, container shipping lines, logistics, oil pipelines, railways, etc. In doing so domain engineers have to decide on such issues as identification of that which is to be described; which of the describable phenomena and concepts are (to be described as) entities, operations, events, and which as behaviours; which entities are (to be described as) continuous which are (...) discrete, which are (...) atomic, which are (...) composite and what are the attributes of either and the mereology of composite entities, i.e., the way in which they are put together from sub-entities. For each of these issues and their composite presentation the domain engineer has to decide on levels of abstraction, what to include and what to exclude. In doing so the domain engineer thus has to have a firm grasp on the a robust understanding and practice of the very many issues of description: what can be described, identifying what is to be described, how to describe, description principles, description techniques, description tools and laws of description. This paper will outline the issues in the slanted type font.