I'm editing a document whose preamble starts with

\documentclass [12pt, a4paper]{extbook}


I wish the chapter 'Introduction and its sections' appear in table contents at the beginning of the text before the unnumbered chapter 1.

I also would like a chapter that I call 'Prelude' and its sections' appear in table contents at the beginning of the text before the unnumbered chapter 1.

How can I do this?

Introduction ................................................. .................

             nontechnical introduction .........................

intrudução technique .................................

structure of the thesis ....................................


Chapter 1 ................................................ ..................

             Section 1 ..................................

Section 2 ..................................

Section 3 ..................................


Chapter 9 ................................................ ................

             Section 1 ..................................

Section 2 ..................................

Section 3 ..................................


Prelude ..................................................................

             Other open issues .........................

New techniques ............................


I think you are looking for the starred versions of the \section, \part etc and a \addcontentsline{toc}{}{}.

For example:

\documentclass[12pt,a4paper]{extbook}

\begin{document}
\tableofcontents
\section*{structure of the thesis}\addcontentsline{toc}{section}{structure of the thesis}

\chapter{Chapter 1}
\section{Section 1}
\section{Section 2}

\chapter{Chapter 9}
\section{Section 1}
\section{Section 2}

\end{document}


An easier solution is to use KOMA-script and the scrbook-class and utilise the addchapand addsec commands. They are similar to the standard commands \chapter and \section except that they are unnumbered. They produce both a running head and an entry in the table of contents.

\documentclass{scrbook}

\begin{document}
\tableofcontents

\chapter{Chapter 1}
\section{Section 1}
\section{Section 2}

\chapter{Chapter 9}
\section{Section 1}
\section{Section 2}