Installation of CL-WHO 1. Probably the easiest way is (load "/path/to/cl-who/load.lisp") This should compile and load CL-WHO on most Common Lisp implementations. 2. With MK:DEFSYSTEM you can make a symlink from 'cl-who.system' to your central registry and then issue the command (mk:compile-system "cl-who") Note that this relies on TRUENAME returning the original file a symbolic link is pointing to. With AllegroCL 6.2 this will only work if you've applied all patches with (SYS:UPDATE-ALLEGRO). 3. You can also use ASDF instead of MK:DEFSYSTEM in a similar way: (asdf:operate 'asdf:compile-op :cl-who) (asdf:operate 'asdf:load-op :cl-who) Complete documentation for CL-WHO can be found in the 'doc' directory. CL-WHO also supports Nikodemus Siivola's HYPERDOC, see and .