This section covers a range of topics that lay out the scientific context of the program. It answers questions such as “what system of units are in use?”, “what is the calculation cycle?”, “what are the conventions of stress notation?”, and the like. It may not be possible to put all this information under one sensible heading; it covers a wide range of subjects that affect the program in different ways. All of this information, however, is necessary to know to be able to use the program.