Frequently Asked Questions about Garnet user interface development environment for Common Lisp and X11 or Macintosh developed by User Interface Software Group, Human-Computer Interaction Institute, Carnegie Mellon University.
A list of questions and answers for the project. It contains both general and technical information: project status, what it is and what it does and how to obtain and configure and run it.
A general introduction to mail filtering on Unix, with information about Procmail, filter, and mailfilter. (Slightly old and apparently no longer maintained, but still an excellent introduction.)