ANSI Common Lisp is a high-level, general-purpose programming language.
GNU CLISP is a Common Lisp implementation by Bruno Haible of Karlsruhe
University and Michael Stoll of Munich University, both in Germany.
It conforms to the ANSI Common Lisp standard, and offers many extensions.
It runs on most GNU and Unix systems (GNU/Linux, GNU/Hurd, FreeBSD, NetBSD,
OpenBSD, Solaris, Tru64, HP-UX, BeOS, IRIX, AIX, Mac OS X and others)
and on other systems (Windows NT/2000/XP/Vista, Windows 95/98/ME)
and needs only 4 MB of RAM.
It is Free Software and may be distributed under the terms of GNU GPL,
while it is possible to distribute commercial proprietary applications
compiled with GNU CLISP.
The user interface comes in English, German, French, Spanish, Dutch,
Russian and Danish, and can be changed during run time.
GNU CLISP includes an interpreter, a compiler, a debugger, CLOS, MOP,
a foreign language interface, a socket interface, i18n, fast bignums,
arbitrary precision floats and more.
An X11 interface is available through CLX, Garnet, CLUE/CLIO.
GNU CLISP runs Maxima, ACL2 and many other Common Lisp packages.

More information at
  <http://clisp.cons.org/>,
  <http://www.clisp.org/>,
  <http://www.gnu.org/software/clisp/> and
  <http://clisp.sourceforge.net/>.
Sources and selected binaries are available by anonymous ftp from
  <ftp://ftp.gnu.org/pub/gnu/clisp/>
and its mirrors.