See the MWE below. How can I achieve (in the standard book class) that despite the oneside option odd and even pages are distinguished in the header? I would like to have that, also with oneside printing, the header of odd pages displays the chapter while the header of even pages displays the section, just as it would be the case without the oneside option.
\documentclass[oneside]{book}
\usepackage{lipsum}
\usepackage{fancyhdr}
\usepackage[
a4paper,
textwidth=16cm,
outer=2cm,
textheight=45\baselineskip,
headheight=\baselineskip,
includehead=true,% Default
heightrounded,
]{geometry}
\pagestyle{fancy}
\fancyhead{}
\fancyhead[LO]{\leftmark}
\fancyhead[RE]{\rightmark}
\fancyhead[LE,RO]{\thepage}
\renewcommand{\headrulewidth}{0pt}
\fancyfoot{}
\begin{document}
\chapter{Chapter One}
\section{Section One of Chapter One}
\lipsum
\lipsum
\section{Section Two of Chapter One}
\lipsum
\lipsum
\end{document}

geometrypackage. – Stephan Lehmke Aug 28 '12 at 9:37\cleardoublepagebehaves like\clearpage... therefore I use the option. Of course, I could redefine\renewcommand{\cleardoublepage}{\clearpage}for the oneside version ... but just now I am not sure whether oneside has further consequences I am overlooking ... – lpdbw Aug 28 '12 at 9:40twosideis the way to go. – Stephan Lehmke Aug 28 '12 at 9:51\renewcommand{\cleardoublepage}{\clearpage}at the beginning of the preamble there are no more blank pages produced by twoside. But how do you solve the problem with changing inner and outer margins? (I edited my question and added my page layout) Ah, I see, it's theasymmetricoption in thegeometrypackage I need. – lpdbw Aug 28 '12 at 10:03