Article 632 of gnu.announce:
The Free Software Foundation sells a number of GNU manuals, to raise
money to pay programmers.  We sell them mainly by mail order and at
conferences.  We would like to sell them in bookstores, too, but as of
now, most bookstores don't carry these books.  They've told us this
was because the covers weren't pretty!

So people who go to the store, looking for books about GNU software,
find only proprietary books (which you are not free to copy).  And if
they buy the proprietary books, little (usually none) of the money
goes to support more free software development.

Well, we have designed prettier cover backgrounds (keeping the amusing
cartoons by Etienne Suvasa), and bookstores seem to like the new
covers when they see them.

Now it's up to you.  If you go to your local technical bookstore and
ask them to carry GNU manuals, they probably will.  (They can carry
FSF CD-ROMs too if they wish.)