\begin{abstract} \sTeX is a collection of {\LaTeX} package that allow to markup documents semantically without leaving the document format, essentially turning {\LaTeX} into a document format for mathematical knowledge management (MKM). \sTeX augments {\LaTeX} with \begin{itemize} \item \emph{Semantic macros} that denote and distinguish between mathematical concepts, operators, etc. independent of their notational presentation, \item A powerful \emph{module system} that allows for authoring and importing individual fragments containing document text and/or semantic macros, independent of -- and without hard coding -- directory paths relative to the current document, \item A mechanism for exporting \sTeX documents to (modular) XHTML, preserving all the semantic information for semantically informed knowledge management services. \end{itemize} \end{abstract}