Free as in Freedom - Richard Stallman's Crusade for Free Software by Sam Williams

A competent biography of the founder of the GNU project, the Free Software Foundation, and creator of GNU Emacs, GCC and the GNU General Public License (GPL).  Stallman comes across as a prickly, awkward man with a mission.  Of his work, the GNU EMACS editor system is now fast fading into antiquity, but the GCC compiler and the GPL are keystones of the GNU/Linux world.  I think that the GPL will probably be what he is remembered for in the long run.

Update on Thu 2004-12-16 by Tristram Brelstaff

Sam Williams has placed a version of this book on-line at http://www.faifzilla.org.  Also, Eric Raymond has some interesting things to say about this book at http://www.catb.org/~esr/writings/rms-bio.html.