Nath is a LaTeX (both 2e and 2.09) style to separate presentation and content in mathematical typography. The style delivers a particular context-dependent presentation on the basis of a rather coarse context-independent notation. Highlighted features: depending on the context, the command \frac produces either built-up or case or solidus fractions, with parentheses added whenever required for preservation of the mathematical meaning; delimiters adapt their size to the material enclosed, rendering \left and \right almost obsolete.