One chapter without numeration

Question

How can I make one chapter (Introduction) without number?

I have:

\documentclass[12pt,a4paper]{mwrep}

\chapter{Introduction}  
\chapter{Chapter 1}  
\chapter{Chapter 2}  

In ToC I have:

1. Introduction ..............1
2. Chapter 1 .................2
3. Chapter 2 .................3

I want to have:

Introduction .................1
1. Chapter 1 .................2
2. Chapter 2 .................3

I want introduction to behave just like the bibliography which is at the same level in ToC as chapters but without number.

Answer 1

For the standard classes (article, report, book) you can use the starred version of \chapter which suppresses the number but also the TOC entry, so you hav to add it manually with \addcontentsline

\documentclass{report}

\begin{document}
\tableofcontents

\chapter*{Introduction}
\addcontentsline{toc}{chapter}{Introduction}  
\chapter{Chapter 1}  
\chapter{Chapter 2} 
\end{document}

or with KOMA-Script (scrartcl,scrreprt,scrbook) which provides \addchap for this case (and \addsec of sections):

\documentclass{scrreprt}

\begin{document}
\tableofcontents

\addchap{Introduction}
\chapter{Chapter 1}  
\chapter{Chapter 2} 
\end{document}

I don’t know about memoire’s behavior when using \chapter

Answer 2

MWCLS supports \chapter* and you don't have to do anything more, it will end in TOC, because Polish rules require it.