Remove hyphens from chapter, section titles

Question

How do I remove hyphenating from all the \part{}, \chapter{}, \section{}, etc., titles of a document?

Answer 1

When disabling hyphenation, be sure to switch from full justification to \raggedright, or \centering in the case of part-level headers

Since you're using the book document class, I suggest you employ the facilities of the sectsty package:

\usepackage{sectsty}
\partfont{\centering}
\chapterfont{\raggedright}
\allsectionsfont{\raggedright}

Answer 2

Hyphenation only occurs with full justification (unless the ragged2e package is employed, hat tip Mico). For large point-size titles, it is frequently disabled by invoking \raggedright. That can be made standard for your document by redefining that particular sectioning command.

For example, you can go to the book documentclass, copy the definitions of the sectioning that requires modification, and use \makeatletter...\makeatother redefinitions to add \raggedright.

I demonstrate it here, mid-document, but you should do it in the preamble.

These sort of changes can also be done with the titlesec package, but I will let someone else post that.

\documentclass{book}
\begin{document}
\section{This is a long title that requires extraordinary hyphenation}

\makeatletter
\renewcommand\section{\@startsection {section}{1}{\z@}%
                                   {-3.5ex \@plus -1ex \@minus -.2ex}%
                                   {2.3ex \@plus.2ex}%
                                   {\normalfont\Large\bfseries\raggedright}}
\makeatother
\section{This is a long title that requires extraordinary hyphenation}

\end{document}