<?xml version="1.0"?>
<section id="licenses-gfdl-section-1" xreflabel="Preamble">
<title>Preamble</title>
<para>The purpose of this License is to make a manual, textbook,
or other functional and useful document <quote>free</quote> in the sense of
freedom: to assure everyone the effective freedom to copy and
redistribute it, with or without modifying it, either commercially
or noncommercially. Secondarily, this License preserves for the
author and publisher a way to get credit for their work, while not
being considered responsible for modifications made by
others.</para>
<para>This License is a kind of <quote>copyleft</quote>, which means that
derivative works of the document must themselves be free in the
same sense. It complements the <xref
linkend="licenses-gfdl-chapter" />, which is a copyleft license
designed for free software.</para>
<para>We have designed this License in order to use it for manuals
for free software, because free software needs free documentation:
a free program should come with manuals providing the same
freedoms that the software does. But this License is not limited
to software manuals; it can be used for any textual work,
regardless of subject matter or whether it is published as a
printed book. We recommend this License principally for works
whose purpose is instruction or reference.</para>
</section>