Guide to LaTeX (4th Edition) (Tools and Techniques

210 Chapter 9. Document Management
applies to all other structure counters. Their correct values can only be
guaranteed when the files have been reprocessed in their proper order.
In spite of these restrictions, the \include command is extremely useful
for large documents, saving considerable computation time. Longer
documents are normally written and edited in many stages. The \include
command permits one to reprocess selective alterations in a short time,
even if the numbering systems temporarily go awry. This can be repaired
later on with a complete reprocessing of the entire document, by
deactivating the \includeonly command in the preamble.
A file that is read in with \include may not contain any \newcounter
declarations. This is not much of a restriction, since they should normally
be given in the preamble.
For example, each chapter of a book might be written to a separate
file with names chap1.tex, chap2.tex, . . . . The processing file itself
contains the text
\documentclass{book}
. . . . . . . . . . . . . . . .
\includeonly{...}
\begin{document}
\frontmatter
\include{toc}
\mainmatter
\include{chap1}
\include{chap2}
. . .
\backmatter
\include{back}
\end{document}
where the file toc.tex contains only commands for the title page, table
of contents, and other listings:
\begin{titlepage} ... \end{titlepage}
\tableofcontents \listoftables \listoffigures
and back.tex those for bibliography and index:
\bibliography{..}
\printindex
The chapters to be processed are selected by adding them to the argument
of \includeonly, not by changing the \include commands, which must
always be present to ensure that all the .aux are input every time. For
example, by giving \includeonly{toc,chap3} one processes the table
of contents and chapter 3.