+@unnumberedsubsubsec Compiling outside the source tree
+
+It is possible to compile LilyPond in a build tree different from the
+source tree, with @code{--srcdir} option of @command{configure}:
+
+@example
+mkdir lily-build && cd lily-build
+@var{sourcedir}/configure --srcdir=@var{sourcedir}
+
+@end example
+
+@node Building documentation
+@subsection Building documentation
+
+This requires a successful compile of LilyPond, or using an external
+LilyPond binary.
+
+@menu
+* Commands for building documentation:: Compiling and installing the documentation.
+* Building documentation without compiling LilyPond:: Using a LilyPond binary already installed.
+@end menu
+
+@node Commands for building documentation
+@unnumberedsubsubsec Commands for building documentation
+
+The documentation is built by issuing
+
+@example
+make web
+@end example
+
+After compilation, the HTML documentation tree is available in
+@file{out-www/offline-root/}, and can be browsed locally.
+
+The HTML and PDF files can be installed into the standard documentation
+path by issuing
+
+@example
+make web-install
+@end example
+
+@noindent
+This also installs Info documentation with images if the installation
+prefix is properly set; otherwise, instructions for manual installation
+of Info documentation are printed on standard output.
+
+It is also possible to build a documentation tree in
+@file{out-www/online-root/}, with special processing, so it can be used
+on a website with content negotiation for automatic language selection;
+this can be achieved by issuing
+
+@example
+make WEB_TARGETS=online web
+@end example
+
+@noindent
+and both @q{offline} and @q{online} targets can be generated by issuing
+
+@example
+make WEB_TARGETS="offline online" web
+@end example
+
+Several targets are available to clean the documentation build and
+help with maintaining documentation; an overview of these targets is
+available with
+
+@example
+make help
+@end example
+
+@noindent
+from every directory in the build tree. Most targets for
+documentation maintenance are available from @file{Documentation/};
+for more information, see @file{Documentation/user/README.txt} and
+@file{Documentation/TRANSLATION}.
+
+@knownissues
+
+If source files have changed since last documentation build, output
+files that need to be rebuilt are normally rebuilt, even if you do not
+run @code{make web-clean} first. However, building dependencies in the
+documentation are so complex that rebuilding of some targets may not
+be triggered as they should be; a workaround is to force rebuilding
+by touching appropriate files, e.g.
+
+@example
+touch Documentation/user/*.itely
+touch input/lsr/*.ly
+@end example
+
+
+@node Building documentation without compiling LilyPond
+@unnumberedsubsubsec Building documentation without compiling LilyPond
+
+The documentation can be built locally without compiling LilyPond
+binary, if LilyPond is already installed on your system.
+
+From a fresh Git checkout, do
+
+@example
+./autogen.sh # ignore any warning messages
+cp GNUmakefile.in GNUmakefile
+make -C python
+nice make LILYPOND_EXTERNAL_BINARY=/path/to/bin/lilypond web
+@end example
+
+Please note that this may break sometimes -- for example, if a new
+feature is added with a test file in input/regression, even the latest
+development release of LilyPond will fail to build the docs.
+
+You may build the manual without building all the @file{input/*}
+stuff: change directory, for example to @file{Documentation/user},
+issue @code{make web}, which will build documentation in a
+subdirectory @file{out-www} from the source files in current
+directory. In this case, if you also want to browse the documentation
+in its post-processed form, change back to top directory and issue
+
+@example
+make out=www WWW-post
+@end example
+
+@knownissues
+
+You may also need to create a script for @command{pngtopnm} and
+@code{pnmtopng}. On GNU/Linux, I use this:
+
+@verbatim
+export LD_LIBRARY_PATH=/usr/lib
+exec /usr/bin/pngtopnm "$@"
+@end verbatim
+
+On MacOS@tie{}X, I use this:
+
+@verbatim
+export DYLD_LIBRARY_PATH=/sw/lib
+exec /sw/bin/pngtopnm "$@"
+@end verbatim
+
+
+