@cindex free documentation@quotation@i{The following article was written by Richard Stallman, founder of theGNU Project.}@end quotationThe biggest deficiency in the free software community today is not inthe software---it is the lack of good free documentation that we caninclude with the free software.  Many of our most importantprograms do not come with free reference manuals and free introductorytexts.  Documentation is an essential part of any software package;when an important free software package does not come with a freemanual and a free tutorial, that is a major gap.  We have many suchgaps today.Consider Perl, for instance.  The tutorial manuals that peoplenormally use are non-free.  How did this come about?  Because theauthors of those manuals published them with restrictive terms---nocopying, no modification, source files not available---which excludethem from the free software world.That wasn't the first time this sort of thing happened, and it was farfrom the last.  Many times we have heard a GNU user eagerly describe amanual that he is writing, his intended contribution to the community,only to learn that he had ruined everything by signing a publicationcontract to make it non-free.Free documentation, like free software, is a matter of freedom, notprice.  The problem with the non-free manual is not that publisherscharge a price for printed copies---that in itself is fine.  (The FreeSoftware Foundation sells printed copies of manuals, too.)  Theproblem is the restrictions on the use of the manual.  Free manualsare available in source code form, and give you permission to copy andmodify.  Non-free manuals do not allow this.The criteria of freedom for a free manual are roughly the same as forfree software.  Redistribution (including the normal kinds ofcommercial redistribution) must be permitted, so that the manual canaccompany every copy of the program, both on-line and on paper.Permission for modification of the technical content is crucial too.When people modify the software, adding or changing features, if theyare conscientious they will change the manual too---so they canprovide accurate and clear documentation for the modified program.  Amanual that leaves you no choice but to write a new manual to documenta changed version of the program is not really available to ourcommunity.Some kinds of limits on the way modification is handled areacceptable.  For example, requirements to preserve the originalauthor's copyright notice, the distribution terms, or the list ofauthors, are ok.  It is also no problem to require modified versionsto include notice that they were modified.  Even entire sections thatmay not be deleted or changed are acceptable, as long as they dealwith nontechnical topics (like this one).  These kinds of restrictionsare acceptable because they don't obstruct the community's normal useof the manual.However, it must be possible to modify all the @emph{technical}content of the manual, and then distribute the result in all the usualmedia, through all the usual channels.  Otherwise, the restrictionsobstruct the use of the manual, it is not free, and we need anothermanual to replace it.Please spread the word about this issue.  Our community continues tolose manuals to proprietary publishing.  If we spread the word thatfree software needs free reference manuals and free tutorials, perhapsthe next person who wants to contribute by writing documentation willrealize, before it is too late, that only free manuals contribute tothe free software community.If you are writing documentation, please insist on publishing it underthe GNU Free Documentation License or another free documentationlicense.  Remember that this decision requires your approval---youdon't have to let the publisher decide.  Some commercial publisherswill use a free license if you insist, but they will not propose theoption; it is up to you to raise the issue and say firmly that this iswhat you want.  If the publisher you are dealing with refuses, pleasetry other publishers.  If you're not sure whether a proposed licenseis free, write to @email{licensing@@gnu.org}.You can encourage commercial publishers to sell more free, copyleftedmanuals and tutorials by buying them, and particularly by buyingcopies from the publishers that paid for their writing or for majorimprovements.  Meanwhile, try to avoid buying non-free documentationat all.  Check the distribution terms of a manual before you buy it,and insist that whoever seeks your business must respect your freedom.Check the history of the book, and try reward the publishers that havepaid or pay the authors to work on it.The Free Software Foundation maintains a list of free documentationpublished by other publishers, at@url{http://www.fsf.org/doc/other-free-books.html}.