\documentclass{scrreprt}

\usepackage[utf8]{inputenc}
\usepackage[T1]{fontenc}
\usepackage[ngerman]{babel}

\title{TOC Demo}
\author{markus schnalke}
\date{2014-05-05}


% \setcounter{tocdepth}{1}  %% TOC only two [sic] levels deep

\begin{document}
\maketitle

\tableofcontents

\clearpage
\section*{Preface}
% manually add an entry to the TOC (without numbering)
\addcontentsline{toc}{section}{Preface}
foo

\chapter{foo}
\section*{XYZ}  %% star makes the section unnumbered
\section{bar}
\subsection{quux}
\subsection{quux}
\section{bar}

\chapter{foo}
\section{bar}
\subsection{quux}
\subsection{quux}
\subsubsection{blubb}
\subsubsection{blubb}
\subsection{quux}
\subsection{quux}
\section{bar}

\chapter{foo}
\section{bar}
\section{bar}
\subsection{quux}
\subsubsection{blubb}
\subsubsection{blubb}
\subsubsection{blubb}
\subsection{quux}
\section{bar}
\subsection{quux}
\subsection{quux}
\section{bar}

\chapter{foo}
\section{bar}
\section{bar}

\chapter{foo}

\chapter{foo}
\section{bar}
\subsection{quux}
\subsubsection{blubb}
\subsubsection{blubb}
\subsection{quux}
\subsection{quux}
\subsection{quux}
\section{bar}
\section{bar}
\subsection{quux}
\subsection{quux}

\chapter*{Literature}
% manually add an entry to the TOC (without numbering)
\addcontentsline{toc}{chapter}{Literature}


\end{document}
