REDUCE is an interactive system for general algebraic computations of interest to mathematicians, scientists and engineers. It can be used interactively for simple calculations but also provides a flexible and expressive user programming language. The development of the REDUCE computer algebra system was started in the 1960s by Anthony C. Hearn. Since then, many scientists from all over the world have contributed to its development. REDUCE has a long and distinguished place in the history of computer algebra systems. Other systems that address some of the same issues but sometimes with rather different emphasis are Axiom, Derive, Macsyma (Maxima), Maple, Mathematica and MuPAD. REDUCE primarily runs on either Portable Standard Lisp (PSL) or Codemist Standard Lisp (CSL), both of which are included in the SourceForge distribution. By modern standards, REDUCE is a surprisingly small and compact application, which runs well on all major operating systems. NOTE: TeX4ht (a part of the texlive package available at SlackBuilds.org) is used to build the REDUCE manual in HTML format. It is not built if TeX4ht is not found on the system. The manual in PDF format is built anyway. The HTML manual is also available on the REDUCE homepage: http://reduce-algebra.sourceforge.net/manual/manual.html