There is a wide spectrum of systems to which a commercial off-the-shelf (COTS) approach might apply, and even the concept of what a COTS-based system 1 is subject to widely varying opinions. So at the outset we must establish our frame of reference. One end of the spectrum of COTS-based systems includes such turnkey systems as Microsoft Office, Common Desktop Environment (CDE), or Netscape Communicator. The capabilities that they provide are valuable, they are reasonably reliable, and they tend to fall into domains where government needs fully conform with the needs of the private sector. Systems of this type are widely and successfully used throughout many government agencies.