# Why are page breaks inserted after sections?

My problem is that page breaks and horizontal lines are inserted after sections, some chapters and the TOC. I have included all the code since I have no clue about which part of it is causing the problem or why.

\documentclass[letterpaper]{book}
\usepackage[spanish]{babel}
\usepackage[utf8]{inputenc}
\usepackage{fancyhdr}
\usepackage{helvet}
\usepackage{wrapfig}
\usepackage[letterpaper, top=4cm, bottom=2.5cm, left=4cm, right=2.5cm]{geometry}
\usepackage{setspace}
\doublespacing
\usepackage[pdftex]{graphicx}
\renewcommand{\familydefault}{\sfdefault}
\pagestyle{fancyplain}
\fancyhf{}
\fancyfoot[R]{\thepage}
\rfoot{\thepage}
\newcommand{\HRule}{\rule{\linewidth}{0.5mm}}

\begin{document}
\frontmatter
%\input{./title.tex}
\tableofcontents
\mainmatter
\section*{MySection}
\chapter{Introduction}
\section{MySection}
\section{MySection}
\section{MySection}
\subsection{subsect}
Lorem  ipsum  dolor  sit  amet,  consectetuer  adipiscing
elit.   Etiam  lobortisfacilisis sem.  Nullam nec mi et
neque pharetra sollicitudin.  Praesent imperdietmi nec ante.
Donec ullamcorper, felis non sodales
\chapter{Chapter2}
\appendix
\chapter{Reproducible Research}
\end{document}


Here is a live document.

The lines are to separate the headers of your pages and the text. You can disable them by setting its width to 0:

\renewcommand{\headrulewidth}{0pt}


It gets set by the fancyhdr package. They are by default disabled on "special" pages, like the first page of the TOC or of chapters, which use a different format.

The empty pages are inserted because every chapter should start as a right page. If you want to disable this (which you really shouldn't), use the openany option:

\documentclass[letterpaper,openany]{book}


You shouldn't put section without a chapter, because that doesn't make sense (your first section*).

• Thanks! This solves the problem with horizontal lines, but the page breaks are still there. – Federico Feb 17 '15 at 22:05
• I've already added that, but please consider if you really want to remove them. – Juri Robl Feb 17 '15 at 22:06