The Programmer's Hierarchical Interactive Graphics System (PHIGS) is a computer-graphics standard defining an interface between an application program and a computer-graphics system. PHIGS has been actively under development since 1980. Much of this development has been performed by Technical Committee X3H3 under the American National Standard Institute (ANSI) procedures. PHIGS is also an international standard sponsored by the United States and developed by the international computer-graphics committee, ISO TC97/SC21/WG2. In addition, PHIGS has been selected as the graphics extension to the X-window standard and as part of the Intel i860 P.A.X. standard. The PHIGS standard has received wide acceptance throughout the computer graphics industry. PHIGS libraries are available on most of the high performance three-dimensional graphics platforms. These include IBM, DEC, HP, Sun, Alliant, Stardent, and Silicon Graphics. Despite this acceptance, there are few texts that provide the software engineer with an overview of the standard. The only currently available PHIGS references are in the form of the ANSI functional description, technical papers, and device-specific PHIGS to the novice PHIGS programmer.