1) NIL is a symbol. Like all symbols, it has a plist (see CLtL p.4 for an example). 2) NIL is a list. Therefore, does (SETQ z NIL) (SETF (GETF z :a) :b) z return NIL or (:a :b)? (That is, does the property go on NIL's plist or directly into the list referenced by z?) Golden Common LISP (ver. 2.2LM) resolves this by having no plist on NIL. I consider this a bug, however. David Loewenstern <dml@nadc>