This appendix is based on the Unix-style man pages included in the plt package. If the man utility is available on your system (it is a standard component of GNU/Linux, Mac OS X, and Unix, and is also part of the Cygwin package for MS-Windows), you should be able to view this material at any time using the command ``man plt'' (or ``man lwcat'', ``man imageplt'', or ``man pltf'').